1.0 Introduction

Tulelake Subbasin DRAFT GSP Revised Public Draft February 18, 2021 1 1.0 Introduction 2 3 1.1 Purpose of the Groundwater Sustainability Plan (GSP or Plan) 4 On September 16, 2014, Governor Jerry Brown signed into law a three-bill legislative package, 5 composed of Assembly Bill (AB) 1739 (Dickinson), Senate Bill (SB) 1168 (Pavley), and SB 1319 6 (Pavley), collectively known as the Sustainable Groundwater Management Act (SGMA), which is 7 codified in Section 10720 et seq. of the California Water Code. The purpose of this 8 Groundwater Sustainability Plan (GSP) is to bring the Klamath River Valley – Tulelake Subbasin 9 (“Tulelake Subbasin” or “Subbasin”), a medium priority basin, into sustainable groundwater 10 management by 2042, which would meet the requirements of SGMA. A GSP is required to be 11 prepared in order to manage a medium-priority basin by January 1, 2022, and to achieve 12 sustainable groundwater management within the subbasin by 2042. Under SGMA, a GSP is 13 prepared and implemented by a Groundwater Sustainability Agency (GSA). 14 15 In SGMA, sustainable groundwater management is defined as management of groundwater 16 supplies in a manner that can be maintained in planning and implementation phases without 17 causing undesirable results. Undesirable results include significant and unreasonable chronic 18 lowering of groundwater levels, reduction of groundwater storage, seawater intrusion, 19 degraded water quality, land subsidence, and interconnected surface waters. 20 21 1.2 Sustainability Goal 22 The sustainability goal for the Tulelake Subbasin is to ensure that by 2042 the Subbasin is being 23 locally managed and operated to maintain a reliable water supply for current and future 24 beneficial uses, without causing undesirable results. More information on the Sustainability 25 Goal and the Sustainable Management Criteria for the Subbasin are located in Section XX. 26 27 1.3 Agency Information (Reg. § 354.6) 28 There are four GSAs in the Tulelake Subbasin: Tulelake Irrigation District (“TID” or “District”) 29 GSA, Modoc County GSA, Siskiyou County GSA, and City of Tulelake GSA, as shown in Figure 1-1. 30 Collectively, these four GSAs will be referred to as “GSAs”. 31

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32 33 Figure 1-1. Location of the Groundwater Sustainability Agencies within the Tulelake Subbasin 34

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35 The Notification of Intent (NOI) filed by the GSAs to develop a Groundwater Sustainable Plan is 36 included in Appendix A. 37 38 Below is the contact information for each of the GSAs and the GSP Plan Manager. 39 40 1.3.1 Tulelake Irrigation District GSA 41 The Tulelake Irrigation District GSA and management area consists of the portion of the 42 Subbasin within the boundary of Tulelake Irrigation District. The mailing address for the 43 Tulelake Irrigation District GSA is: 44 45 Tulelake Irrigation District GSA 46 P.O. Box 699 47 Tulelake, CA 96134 48 49 1.3.2 Modoc County GSA 50 The Modoc County GSA and management area consists of the portion of the Subbasin within 51 the jurisdictional boundary of Modoc County, and outside the boundary of TID. Modoc County 52 meets the requirements of a severely disadvantaged community. The mailing address for the 53 Modoc County GSA is: 54 55 Clerk of the Board 56 204 S. Court Street 57 Alturas, CA 96101 58 59 1.3.3 Siskiyou County 60 The Siskiyou County GSA and management area consists of the portion of the Subbasin within 61 the jurisdictional boundary of Siskiyou County, and outside the boundary of TID. Siskiyou 62 County meets the requirements of a disadvantaged community. The mailing address for the 63 Siskiyou County GSA is: 64 65 County Clerk 66 510 North Main St. 67 Yreka, CA 96097 68 69 1.3.4 City of Tulelake

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70 The City of Tulelake GSA and management area consists of the portion of the Subbasin within 71 the jurisdictional boundary of the City of Tulelake. The mailing address for the City of Tulelake 72 GSA is: 73 74 City Clerk 75 P.O. Box 847 76 Tulelake, CA 96134 77 78 1.3.5 Tulelake Subbasin GSP Plan Manager 79 SGMA Regulation § 354.6(c) requires that the GSP provide the contact information for the plan 80 manager. The contact information for the Tulelake Subbasin GSP is: 81 82 Brad Kirby 83 Tulelake Irrigation District GSA 84 P.O. Box 699 85 Tulelake, CA 96134 86 Phone: (530) 667-2249 87 Email: [email protected] 88 89 1.3.1 Organization and Management Structure of the Groundwater Sustainability Agency 90 (GSA or Agency)

91 During August 2017, the GSAs executed a “Memorandum of Understanding Regarding 92 Development and Implementation of a Groundwater Sustainability Plan for the Tulelake 93 Groundwater Subbasin” (MOU). The MOU is provided as Appendix B to this document. The 94 MOU established the Tulelake Subbasin GSP’s Core Team (Core Team), comprised of 95 representatives from each GSA and responsible for directing and coordinating the 96 development, financing, and implementation of the GSP, and satisfying the requirements of 97 SGMA. In addition, a diverse group of advisory members who were selected through an 98 application process, informed the Core Team during GSP development. The advisory members 99 consist of an environmental conservation water user, residential domestic water user, 100 agricultural groundwater/surface water user, and Oregon groundwater/surface water user. See 101 Appendix C for a list of the advisory members. 102 103 1.3.2 Legal Authority of the GSA

104 Tulelake Irrigation District, Modoc County, Siskiyou County, and the City of Tulelake are local 105 public agencies with existing statutory authorities who decided to each form a GSA. The MOU 4

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106 (see Appendix B) between the four GSAs describes the additional authorities provided to the 107 GSAs by SGMA. In addition, the MOU memorialized the GSA’s intent to exercise their existing 108 authorities and those provided by SGMA in order to develop and implement this GSP. 109 110 1.3.3 Estimated Cost of Implementing the GSP and the GSA’s Approach to Meet Costs

111 Development of this GSP was substantially funded through a Proposition 1 Sustainable 112 Groundwater Planning Grant. The implementation of the GSP and future SGMA compliance will 113 be highly dependent upon management actions, if necessary. Costs for management actions 114 will be shared by the GSAs based on action beneficiaries. The primary ongoing cost will be for 115 GSP administration, which includes annual reports and 5 year updates. These costs will be 116 shared by the GSAs in accordance with the budget proportions outlined in the MOU. 117 Implementation of the GSP is estimated to cost between $X and $X per year. 118 119 1.4 GSP Organization 120 This GSP is organized in a manner consistent with DWR’s “Groundwater Sustainability Plan 121 (GSP) Annotated Outline”. In addition, during the preparation of this GSP, DWR’s “Preparation 122 Checklist for GSP Submittal” was utilized. A completed checklist can be found in Table 1-1. 123

Tulelake Subbasin DRAFT GSP Revised Public Draft February 18, 2021 Table 1-1. Preparation Checklist for GSP Submittal GSP Section(s) or Page Water Code Regulations Requirement Description Number(s) in the Section Section GSP Article 3. Technical and Reporting Standards • Monitoring protocols adopted by the GSA for data collection and management • Monitoring protocols that are designed to detect changes in Monitoring groundwater levels, groundwater quality, inelastic surface 352.2 Protocols subsidence for basins for which subsidence has been identified as a potential problem, and flow and quality of surface water that directly affect groundwater levels or quality or are caused by groundwater extraction in the basin Article 5. Plan Contents, Sub-article 1. Administrative Information • Executive Summary 354.4 General Information • List of references and technical studies • GSA mailing address • Organization and management structure 354.6 Agency Information • Contact information of Plan Manager • Legal authority of GSA • Estimate of implementation costs • Area covered by GSP • Adjudicated areas, other agencies within the basin, and areas covered by an Alternative 354.8(a) 10727.2(a)(4) Map(s) • Jurisdictional boundaries of Federal or State land • Existing land use designations • Density of wells per square mile

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Description of the 354.8(b) Plan Area

• Description of water resources monitoring and management programs Water Resource 354.8(c) • Description of how the monitoring networks of those plans Monitoring and 354.8(d) 10727.2(g) will be incorporated into the GSP Management 354.8(e) • Description of how those plans may limit operational flexibility Programs in the basin • Description of conjunctive use programs • Summary of general plans and other land use plans • Description of how implementation of the GSP may change water demands or affect achievement of sustainability and how the GSP addresses those effects Land Use Elements • Description of how implementation of the GSP may affect the or Topic Categories 354.8(f) 10727.2(g) water supply assumptions of relevant land use plans of Applicable • Summary of the process for permitting new or replacement General Plans wells in the basin • Information regarding the implementation of land use plans outside the basin that could affect the ability of the Agency to achieve sustainable groundwater management

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GSP Section(s) or Page Water Code Regulations Requirement Description Number(s) in the Section Section GSP Article 5. Plan Contents, Sub-article 1. Administrative Information (Continued) Description of Actions related to: • Control of saline water intrusion • Wellhead protection • Migration of contaminated groundwater • Well abandonment and well destruction program • Replenishment of groundwater extractions • Conjunctive use and underground storage • Well construction policies Additional GSP 354.8(g) 10727.4 • Addressing groundwater contamination cleanup, recharge, Contents diversions to storage, conservation, water recycling, conveyance, and extraction projects • Efficient water management practices • Relationships with State and Federal regulatory agencies • Review of land use plans and efforts to coordinate with land use planning agencies to assess activities that potentially create risks to groundwater quality or quantity • Impacts on groundwater dependent ecosystems • Description of beneficial uses and users • List of public meetings • GSP comments and responses Notice and 354.10 • Decision-making process Communication • Public engagement • Encouraging active involvement • Informing the public on GSP implementation progress

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GSP Section(s) or Page Water Code Regulations Requirement Description Number(s) in the Section Section GSP Article 5. Plan Contents, Sub-article 2. Basin Setting • Description of the Hydrogeologic Conceptual Model • Two scaled cross-sections Hydrogeologic 354.14 • Map(s) of physical characteristics: topographic information, Conceptual Model surficial geology, soil characteristics, surface water bodies, source and point of delivery for imported water supplies • Map delineating existing recharge areas that substantially Map of Recharge 354.14(c)(4) 10727.2(a)(5) contribute to the replenishment of the basin, potential Areas recharge areas, and discharge areas • Description of how recharge areas identified in the plan 10727.2(d)(4) Recharge Areas substantially contribute to the replenishment of the basin 10727.2(a)(1) Current and • Groundwater elevation data Historical • Estimate of groundwater storage Groundwater • Seawater intrusion conditions 354.16 • Groundwater quality issues 10727.2(a)(2) • Land subsidence conditions Conditions • Identification of interconnected surface water systems • Identification of groundwater-dependent ecosystems • Description of inflows, outflows, and change in storage • Quantification of overdraft Water Budget 354.18 10727.2(a)(3) • Estimate of sustainable yield Information • Quantification of current, historical, and projected water budgets • Description of surface water supply used or available for use 10727.2(d)(5) Surface Water Supply for groundwater recharge or in-lieu use

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GSP Section(s) or Page Water Code Requirement Description Regulations Section Number(s) in the Section GSP Article 5. Plan Contents, Sub-article 2. Basin Setting (Continued) • Reason for creation of each management area • Minimum thresholds and measurable objectives for each management area • Level of monitoring and analysis 354.20 Management Areas • Explanation of how management of management areas will not cause undesirable results outside the management area • Description of management areas

Article 5. Plan Contents, Sub-article 3. Sustainable Management Criteria 354.24 Sustainability Goal • Description of the sustainability goal • Description of undesirable results • Cause of groundwater conditions that would lead to undesirable results 354.26 Undesirable Results • Criteria used to define undesirable results for each sustainability indicator • Potential effects of undesirable results on beneficial uses and users of groundwater • Description of each minimum threshold and how they were established for each sustainability indicator • Relationship for each sustainability indicator 10727.2(d)(1) • Description of how selection of the minimum threshold may 354.28 Minimum Thresholds 10727.2(d)(2) affect beneficial uses and users of groundwater • Standards related to sustainability indicators • How each minimum threshold will be quantitatively measured

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GSP Section(s) or Page Water Code Regulations Requirement Description Number(s) in the Section Section GSP Article 5. Plan Contents, Sub-article 3. Sustainable Management Criteria (Continued) • Description of establishment of the measureable objectives for each sustainability indicator 10727.2(b)(1) • Description of how a reasonable margin of safety was 10727.2(b)(2) Measureable 354.30 established for each measureable objective 10727.2(d)(1) Objectives • 10727.2(d)(2) Description of a reasonable path to achieve and maintain the sustainability goal, including a description of interim milestones Article 5. Plan Contents, Sub-article 4. Monitoring Networks • Description of monitoring network • Description of monitoring network objectives • Description of how the monitoring network is designed to: demonstrate groundwater occurrence, flow directions, and hydraulic gradients between principal aquifers and surface water features; estimate the change in annual groundwater in storage; monitor seawater intrusion; determine groundwater quality trends; identify the rate and extent of 10727.2(d)(1) land subsidence; and calculate depletions of surface water 10727.2(d)(2) 354.34 Monitoring Networks caused by groundwater extractions 10727.2(e) • Description of how the monitoring network provides 10727.2(f) adequate coverage of Sustainability Indicators • Density of monitoring sites and frequency of measurements required to demonstrate short-term, seasonal, and long- term trends • Scientific rational (or reason) for site selection • Consistency with data and reporting standards • Corresponding sustainability indicator, minimum threshold, measureable objective, and interim milestone 11

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GSP Section(s) or Page Water Code Regulations Requirement Description Number(s) in the Section Section GSP (Monitoring Networks Continued) • Location and type of each monitoring site within the basin displayed on a map, and reported in tabular format, including information regarding the monitoring site type, frequency of measurement, and the purposes for which the monitoring site is being used • Description of technical standards, data collection methods, and other procedures or protocols to ensure comparable data and methodologies

• Description of representative sites • Demonstration of adequacy of using groundwater elevations Representative as proxy for other sustainability indicators 354.36 Monitoring • Adequate evidence demonstrating site reflects general conditions in the area

• Review and evaluation of the monitoring network • Identification and description of data gaps Assessment and • Description of steps to fill data gaps 354.38 Improvement of • Description of monitoring frequency and density of sites Monitoring Network

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GSP Section(s) or Page Water Code Regulations Requirement Description Number(s) in the Section Section GSP Article 5. Plan Contents, Sub-article 5. Projects and Management Actions • Description of projects and management actions that will help achieve the basin’s sustainability goal • Measureable objective that is expected to benefit from each project and management action • Circumstances for implementation • Public noticing • Permitting and regulatory process • Time-table for initiation and completion, and the Projects and accrual of expected benefits 354.44 Management Actions • Expected benefits and how they will be evaluated • How the project or management action will be accomplished. If the projects or management actions rely on water from outside the jurisdiction of the Agency, an explanation of the source and reliability of that water shall be included. • Legal authority required • Estimated costs and plans to meet those costs • Management of groundwater extractions and recharge

354.44(b)(2) 10727.2(d)(3) • Overdraft mitigation projects and management actions

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GSP Section(s) or Page Water Code Regulations Requirement Description Number(s) in the Section Section GSP

Article 8. Interagency Agreements Coordination Agreements shall describe the following: • A point of contact • Responsibilities of each Agency • Procedures for the timely exchange of information between Agencies Coordination • Procedures for resolving conflicts between Agencies Agreements - Shall be • How the Agencies have used the same data and submitted to the methodologies to coordinate GSPs Department together • How the GSPs implemented together satisfy the 357.4 10727.6 with the GSPs for the requirements of SGMA basin and, if approved, • Process for submitting all Plans, Plan amendments, shall become part of supporting information, all monitoring data and other the GSP for each pertinent information, along with annual reports and participating Agency. periodic evaluations • A coordinated data management system for the basin • Coordination agreements shall identify adjudicated areas within the basin, and any local agencies that have adopted an Alternative that has been accepted by the Department

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1 2.0 Plan Area 2 3 2.1 Description of the Plan Area (Reg. § 354.8) 4 This GSP covers the entire Tulelake Subbasin which covers approximately 60,000 acres of 5 irrigated land near the California-Oregon border. The Subbasin is part of the larger Upper 6 Klamath Basin, which extends into Oregon and is located within the North Coast Hydrologic 7 Region. The majority of the Subbasin lies in the Tulelake Irrigation District and is within Modoc 8 County and Siskiyou County. Figure 1-1 shows the location of the GSAs within the Subbasin. 9 10 2.1.1 Summary of Jurisdictional Areas and Other Features (Reg. § 354.8b)

11 Jurisdictional areas and other features, with the exception of the GSAs, include an agricultural 12 water purveyor, a city, an unincorporated town, and public lands. There are no areas within the 13 Subbasin covered by an Alternative Plan. 14 15 2.1.1.1 Adjudicated Areas

16 The Subbasin is located within the southeastern region of the Upper Klamath Basin (see Figure 17 2-1). 18

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20 21 Figure 2-1. Upper Klamath Basin Boundary and Tulelake Subbasin Boundary.

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22 In 1902, Congress enacted the Reclamation Act (1902 Act). Construction of the Klamath 23 Reclamation Project began in 1906. Prior to construction of the Klamath Project, most of the 24 lands located within the current boundary of the District were submerged during certain times 25 of the year, depending upon hydrologic conditions. The submergence of this land created a 26 body of water known as Tulelake. In October 1909, two outlets were constructed at the 27 southern end of Tulelake and the reclamation of lands submerged by Tulelake began. The 28 draining of Tulelake continued until 1912 when the level of the lake became too low to 29 continue utilizing the outlets. 30 31 Construction of the Klamath Basin Project continued during the early 1900s, and by 1910 Clear 32 Lake Dam was completed. By the spring of 1912, the Lost River Diversion Dam and Channel 33 were complete. These facilities diverted water from the Lost River to the Klamath River and 34 reduced flows into Tulelake. In 1916, work began on the Tulelake unit with the construction of 35 distribution and drainage systems for exposed lands along the northern portion of Tulelake. By 36 1916, approximately 5,900 acres within the previously submerged region of Tulelake had been 37 exposed. In 1917, the first Tulelake lands opened to homestead entry. In 1920, Anderson‐Rose 38 Dam was constructed. Work also began on the J‐Canal which was completed in 1923. During 39 the 1920s and 1930s, work on the distribution and drainage systems continued within the 40 Tulelake area. By 1923, the continued diversion of Lost River water into the Klamath River and 41 diversion for irrigation resulted in approximately 85,000 acres of the previously submerged 42 90,000 acres of Tulelake being available for farming. During the late 1920s, as much as 50,000 43 acres were being farmed. 44 45 Reclaimed lands were made available to settlers and homesteaded under public notices issued 46 from the 1920s to 1940s. Lands were typically leased to private individuals, prior to homestead 47 entry. In 1940, work began on the D‐Pumping Plant. This pumping plant and the Tulelake 48 Tunnel were completed in November 1941. During World War II, about 44,000 acres owned by 49 the United States within Tulelake were leased for farming. The Copic Bay region of Tulelake was 50 opened to homesteading in 1947 and 1948. By the 1950s, about 44,000 acres had been 51 homesteaded. 52 53 In 1950, the U.S. Bureau of Reclamation (Reclamation) required the organization of an irrigation 54 district in the Tulelake area. By 1952, Tulelake Irrigation District had been formed and was 55 holding regular meetings. On September 10, 1956, the District entered into a contract with 56 Reclamation for repayment of the construction charges, and to transfer to the District the 57 operation and maintenance of the facilities used to deliver water to lands within the District. 58 Following the formation of the District, and the execution of Contract No. 14-06-200-5954

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59 between the District and the United States, the District began providing water service to lands 60 within its boundary. The Klamath River water rights for the Klamath Project are currently being 61 adjudicated by the State of Oregon. Contractually, Reclamation recognizes certain lands within 62 the District as having a higher priority to Klamath Project supplies than other lands. The District 63 is an active participant in the ongoing Klamath River Adjudication. 64 65 Two contracts with irrigation districts in the Klamath Project were made, pursuant to the 1902 66 Act, and related authority to serve lands in the “Main Division” and “Modoc Division” of the 67 Klamath Project. The “Modoc Division” is in the Tulelake Division, and the contract with the 68 District was made pursuant to the 1902 Act and Section 9(d) of the Reclamation Project Act of 69 1939, and other legislation. The District’s contract does not specify a duty or rate of diversion. 70 Rather, it provides for the repayment of the construction costs of the Klamath Project by the 71 District in consideration for the right to divert and deliver to their members that amount of 72 water that can be applied to the crops beneficially and without waste. 73 74 Oregon State water rights were issued through the Final Order of Determination of the Klamath 75 Adjudication. The Final Order of Determination was issued in 2013, with amendments and 76 corrections incorporated during 2014. Following the release of the Final Order of 77 Determination, the adjudicatory judicial process will continue with an uncertain end date. The 78 District was associated with the consolidated claim (Claim No. 321-17, 293, 323-3) and Claims 79 312 and 317. The claim numbers, description, and associated acreages are as follows: 80 Claim # Description/Acres 293 215,559.4 acres agriculture & refuge lands + 15,659.00 acres of inchoate lands 312 35,000 acre-feet of water per year for irrigation of up to a maximum of 10,000 acres per year within a place of use totaling 25,881.7 acres within Lower Klamath National Wildlife Refuge 317 49,902.3 acre-feet of water per year for irrigation of up to a maximum of 16,000 acres per year within a place of use totaling 17,967.3 acres within Tulelake National Wildlife Refuge 321 178,857.81 acres 3280cfs from Upper Klamath Lake (UKL), Lake Ewauna, Link River, & Klamath River including LRDC & all tributaries to Klamath River 323 735,500 Acre Feet storage in UKL, Agency Lake, & Lake Ewauna 18,500 Acre feet 81

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82 The water rights acquired for the Klamath Project are for the benefit of all Klamath Project 83 lands including those lands within the District and the other entities served by the Klamath 84 Project canal system, which are operated and maintained by Klamath Project districts. 85 86 As part of the Final Order of Determination, the total amount of water that could be diverted by 87 the combined irrigation system of Klamath Irrigation District (KID) and the District was 88 estimated based on the history of the use of water from the combined KID/District system 89 between 1961 and 2000. The total quantity of water for the KID/District system includes water 90 delivered to federal lands, namely Tulelake National Wildlife Refuge, under Claim 317. This 91 estimate includes the March 1 through October 31 season, and the February 15 through 92 November 15 season, recognized for use of water from Station 48 and the No. 1l Drain Gate. 93 94 In addition, lands within the District have the right to use water from Lost River. Although some 95 Lost River water rights were adjudicated in 1918, a recent court decision ruled that the 1918 96 process had not adjudicated water rights in the Project. There is some uncertainty on this issue. 97 Some lands may possess California riparian rights to Lost River or Tulelake. 98 99 2.1.1.2 Other Agencies Within the Basin and Areas Covered by an Alternative Plan (Reg. § 100 354.8a)

101 This GSP, prepared with input from all GSAs within the Subbasin, covers the entirety of the 102 Subbasin. The Subbasin is an isolated basin not immediately adjoined to any other subbasins in 103 California. Therefore, no alternative plans have been submitted for any part of the Subbasin, 104 nor any immediately surrounding subbasin. A map is not included with this section because 105 there are not any other Agencies or alternative plans within the Subbasin. 106 107 2.1.1.3 Jurisdictional Boundaries of Federal or State Land (Reg. § 354.8a)

108 Figure 2-2 shows jurisdictional boundaries of Modoc County, Siskiyou County, the City of 109 Tulelake, and the unincorporated community of Newell within the Subbasin. In addition, 110 Westside Irrigation District is identified, which receives delivered water via District conveyance 111 facilities. 112

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113 114 Figure 2-2. Jurisdictional boundaries within the Tulelake Subbasin 115

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116 Figure 2-2 also shows the Tulelake National Wildlife Refuge (TLNWR) within the Subbasin. 117 TLNWR is located within the southwest portion of the District boundary and totals 118 approximately 40,000 acres, of which approximately 17,300 acres are leased to farmers or 119 farmed by refuge permit holders. Grain, row crop, and alfalfa are typically produced on these 120 lands. These crops, together with the waste grain from the lease program, are a major food 121 source for migrating and wintering waterfowl. The remaining acreage is open water in Sumps 122 1A and 1B or permanent or seasonal wetlands, or areas of emergent vegetation. The refuge, 123 along with the Lower Klamath National Wildlife Refuge, is located at the downgradient end of 124 Reclamation’s Klamath Project. Excess water not used on the refuges is ultimately pumped back 125 into the Klamath River through the Klamath Straights Drain. 126 127 2.1.1.4 Existing Land Use Designations (Reg. § 354.8a)

128 The plan area consists of approximately 60,000 acres of irrigated land. Crop types within the 129 District are relatively consistent on a year-to-year basis and include alfalfa, cereal grains, mint, 130 onions, pasture, potatoes, and other miscellaneous crops. In 2014, the California Department 131 of Water Resources (DWR) contracted with Land IQ to conduct statewide land use surveys 132 using satellite imagery. Figure 2-3 identifies the cropping pattern from these surveys within the 133 plan area to provide a general idea of existing land use. These categorizations were focused on 134 distinguishing cropland from other land uses, with less focus on specific subcategories for 135 managed wetlands or other habitats. More information on groundwater dependent ecosystems 136 can be found in Section X. 137

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138 139 Figure 2-3. Tulelake Subbasin 2014 Crop Map 140

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141 2.1.1.5 Identification of Water Use Sector and Water Source Type (Reg. § 354.8a)

142 The majority of the District’s surface water supply is from the Klamath River, and is directed to 143 the District through an intertie between the Klamath River and the Lost River, known as the 144 Lost River Diversion Channel. Klamath River water is diverted at locations on the Lost River 145 Diversion Channel known as Station 48 and the No. 1 Drain during the irrigation season. These 146 diversions provide Klamath River flows to the District and other water users. The District also 147 receives tailwater from Klamath River water users located north of the California-Oregon State 148 Line, including lands within the Klamath Irrigation District. At times, the Lost River provides 149 some surface water supply during the irrigation season to the District. The Lost River supply is 150 infrequent and unreliable for irrigation needs. 151 152 The District operates and maintains a diversion dam on the Lost River Channel, known as the 153 Anderson-Rose Dam, located less than one-mile north of the California-Oregon State Line. The 154 Anderson-Rose Dam is operated to deliver surface water into the District’s J-Canal, which 155 distributes water to more than one-half of the District’s irrigated lands through turnouts and 156 lateral canals. The J-Canal also conveys water to other canal systems for delivery to additional 157 lands within the District. Water not diverted by the District at Anderson-Rose Dam flows 158 through the Lost River and into the Tulelake Sumps. Water regulated and stored within the 159 Tulelake Sumps may be diverted or re-diverted for irrigation within the District or discharged by 160 the District’s D-Pumping Plant to the P-Canal, which becomes available to the Lower Klamath 161 National Wildlife Refuge (LKNWR) and the water users on the P-Canal system of the Klamath 162 Project. The operational spills and tailwater resulting from irrigation within the District are 163 conveyed through the District’s extensive drainage system, which utilizes gravity and pumped 164 discharge into portions of the canal system or into the Tulelake Sumps. 165 166 Figure 2-4 identifies the major water conveyance system facilities within the Klamath Project. 167

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168 169 Figure 2-4. Klamath Project Conveyance Facilities 170 171 Figure 2-5 identifies the major facilities within the District, including the conveyance and 172 drainage system. 173

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174 175 Figure 2-5. District Conveyance and Drainage Facilities 176

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177 Most of the areas of the District conjunctively use surface water and groundwater. Therefore, 178 in addition to the surface water supply discussed previously, many private landowners within 179 the District own and operate private groundwater wells. In addition, in 2001, the District 180 constructed 10 groundwater wells to provide supplemental water supplies during drier years. 181 Typically, groundwater is only utilized within the District during years where surface water 182 supplies do not meet agricultural demands, and represents a small portion of the total water 183 supplies available in any given year. 184 185 2.1.1.6 Inventory and Density of Wells per Square Mile (Reg. § 354.8a)

186 Table 2-1 below provides an inventory of wells within the Tulelake Subbasin by county and 187 type. DWR maintains a well completion report database, which was utilized to prepare this 188 table. 189 190 Table 2-1: Well Inventory Type of Well Modoc County Total Wells Siskiyou County Total Wells Agricultural 94 16 Industrial 1 4 Monitoring 13 58 Miscellaneous1 11 36 Domestic & Public Supply 108 41 Total 227 155 191 Source: DWR Well Completion Report Database, downloaded January 2021 192 1 This category includes the following planned uses identified in the DWR Well Completion Report Database: Other, 193 Other Destroyed, Other Not Specified, Other Unknown, Injection, Sparging, Test Well, Vapor Extraction 194 Based on the data from the DWR Well Completion Report Database, there are 382 wells in the 195 Subbasin, and 311 of those are assumed to be production wells (i.e., not monitoring wells). It is 196 unknown how many of these wells are actively used or how many of these wells have been 197 abandoned and/or destroyed as this information is not always reported. 198 199 Using the information from Table 2-1, Figure 2-6, Figure 2-7, and Figure 2-8 identify the density 200 of wells per square mile for agricultural wells, industrial/monitoring/miscellaneous wells, and 201 domestic wells, respectively. Each of the squares on the figures represent approximately one 202 square mile of land. The color of each square indicates the number of wells in the square. 203

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204 205 Figure 2-6. Density of Agricultural Wells per square mile 206

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207 208 Figure 2-7. Density of Industrial/Monitoring/Miscellaneous Wells per square mile

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209 210 Figure 2-8. Density of Domestic and Public Supply Wells per square mile 211

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212 2.1.2 Water Resources Monitoring and Management Programs (Reg. § 354.8 c, d, e)

213 The following section provides information, relative to various water resources monitoring and 214 management programs, within the Subbasin. These programs provide valuable information that 215 assisted with the development of this GSP and will also help with implementation of the GSP. 216 These existing programs support water management in the Subbasin and do not limit 217 operational flexibility. 218 219 2.1.2.1 Groundwater Management Plan (2013)

220 In 2013, the District prepared and adopted a Groundwater Management Plan (GWMP), as 221 authorized by sections 10753-10753.11 of the California Water Code. The preparation of the 222 GWMP included the development of appropriate groundwater “Management Objectives” 223 within the GWMP area (District boundary), and the corresponding monitoring to ensure that 224 the Management Objectives are being met. The primary goal in developing the GWMP was to 225 work cooperatively with landowners within the District to most efficiently monitor the 226 groundwater resources and to continue with an efficient and effective conjunctive use 227 operation during years where surface water supplies are limited or not available. 228 229 The 2013 GWMP provides valuable information and a framework of management objectives 230 that align with the goals of this GSP. 231 232 2.1.2.2 Water Management Plan (2017)

233 In 2017, the District prepared and adopted a Water Management Plan (WMP) in compliance 234 with U.S. Bureau of Reclamation’s Water Management Plan 2017 Standard Criteria (2017 235 Standard Criteria). As part of the WMP preparation process, implementation of Critical Best 236 Management Practices (Critical BMPs) was required. The Critical BMPs include: 237 • Measure the volume of water delivered by the District to each turnout with devices that 238 are operated and maintained to a reasonable degree of accuracy, under most 239 conditions, to ± 6% 240 • Designate a water conservation coordinator to develop and implement the Plan and 241 develop progress reports 242 • Provide or support the availability of water management services to water users 243 • Pricing structure – based at least in part on quantity delivered 244 • Evaluate and improve efficiencies of District pumps

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245 In addition to the Critical BMPs identified above, the 2017 Standard Criteria identified 246 Exemptible BMPs which are required, unless an exemption from Reclamation is approved. The 247 Exemptible BMPs include: 248 • Facilitate alternative land use 249 • Facilitate use of available recycled water that otherwise would not be used beneficially, 250 meets all health and safety criteria, and does not cause harm to crops or soils 251 • Facilitate the financing of capital improvements for on-farm irrigation systems 252 • Incentive pricing 253 • Canal lining/piping and regulatory reservoirs 254 • Increase flexibility in water ordering by, and delivery to, water users (within operational 255 limits) 256 • Construct and operate contractor spill and tailwater recovery systems 257 • Plan to measure outflow 258 • Optimize conjunctive use 259 • Automate distribution and/or drainage system structures 260 • Facilitate or promote water user pump testing and evaluation 261 • Mapping 262 263 The 2017 WMP provides valuable information and a framework of best management practices 264 that align with the goals of this GSP. 265 266 2.1.2.3 CASGEM Monitoring

267 The California Statewide Groundwater Elevation Monitoring program (CASGEM) is a state-wide 268 initiative to collect groundwater elevations and facilitate collaboration between local 269 monitoring entities and DWR. The District enrolled in the CASGEM program on behalf of its 270 landowners in 2010. Participation by the District includes working cooperatively with DWR in 271 order to monitor groundwater elevations within the groundwater well monitoring network. The 272 District plans to import the wells identified in Section X “Monitoring Network” into DWR’s GSP 273 Reporting System and Monitoring Network Module, which along with the District’s internal 274 data management system will serve as the GSAs Data Management System. This centralized 275 groundwater level data storage platform will assist with collection, reporting, and sharing with 276 DWR. 277 278 2.1.2.4 Groundwater Extraction Monitoring

279 The District monitors groundwater extractions from District operated wells on a monthly basis 280 while the wells are in operation. These records are maintained by the District. The City of 31

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281 Tulelake monitors groundwater extractions from its wells. During the water bank programs 282 discussed in Section 2.1.2.10, participating wells, which include both District operated wells and 283 private wells, are monitored on a monthly basis. 284 285 2.1.2.5 Groundwater Quality Monitoring

286 The State Water Resource Control Board’s 2009 Recycled Water Policy (amended in 2013) 287 required that local water and wastewater entities in priority basins develop Salt and Nutrient 288 Management Plans (SNMPs). The Tulelake Subbasin was classified as a “Low Use” basin under 289 the policy and therefore did not have to prepare a plan. 290 291 The U.S. Geological Survey (USGS) collects groundwater quality data on a regular basis under 292 the Groundwater Ambient Monitoring and Assessment Program (GAMA). These data are stored 293 in the GAMA online database. 294 295 2.1.2.6 Irrigated Lands Regulatory Program

296 The Irrigated Land Regulatory Program (ILRP) was initiated in 2003 to regulate agricultural 297 runoff to surface waters and groundwater. The North Coast Regional Water Quality Control 298 Board is currently working on an approach to address discharges of waste associated with 299 agricultural lands in the Tulelake Subbasin. 300 301 2.1.2.7 Land Subsidence Monitoring

302 Monitoring of land subsidence within the Upper Klamath Basin and the Tulelake Subbasin has 303 been limited. Historically, land subsidence was monitored along transects by comparing 304 periodic spirit level surveys conducted by the USGS and the National Geodetic Survey (NGS). In 305 the mid‐1980s, a transition was made from the spirit level surveys to global positioning system 306 (GPS) surveys. Like spirit level transects, GPS monitoring of subsidence relies on periodic 307 resurveying of a network of monuments. In 2001, DWR defined a network of 23 stations. In 308 2011, DWR re‐surveyed 6 of the 23 monuments along the east and southeast portion of the 309 Subbasin to identify any potential land subsidence. Results from the 2011 survey indicate that 310 there has been no noticeable subsidence on the east side of the Subbasin. 311 312 2.1.2.8 Surface Water Diversion Monitoring

313 The District, along with other water users in the Klamath Project, and in coordination with 314 Reclamation, monitors surface water diversions within the Klamath Project. Reclamation

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315 maintains historical diversion information for the Klamath Project. In addition, the District 316 maintains similar records for its diversions. 317 318 2.1.2.9 County Ordinances and Permitting

319 Siskiyou and Modoc Counties have provisions in their ordinances for groundwater management 320 and use. In general, these county ordinances which outline a permit process for groundwater 321 extraction for use outside of each respective county do not apply to the District and the GSP 322 area. There are specific provisions in each county ordinance that allow for the use of water 323 within the boundaries of a district which is in part located within one county and in part in 324 another county (or counties) where such extraction quantities and use are consistent with 325 historical practices of a District. These provisions are consistent with current District operations. 326 327 Well construction permitting within the Subbasin is administered by the Modoc and Siskiyou 328 County Health Departments, which effectively implement the State Well Standards for water 329 wells and monitoring wells. Permitting of municipal supply wells is also within the purview of 330 the State Department of Public Health. 331 332 2.1.2.10 Water Bank Programs

333 Water banks were initiated in the Klamath Project based on various needs. The original 334 facilitating entity for the water bank programs was Reclamation. Following the formation of the 335 Klamath Water and Power Agency (KWAPA) in 2008, a cooperative agreement between 336 Reclamation and KWAPA was initiated, resulting in the Water User Mitigation Program 337 (WUMP). KWAPA dissolved in 2016, and the Klamath Project Drought Response Agency 338 (KPDRA) was formed in 2018 to facilitate future programs. The goal of the implementation of 339 the water bank programs was to develop a market-based approach in which water was 340 purchased by a single buyer (Reclamation/KWAPA/KPDRA) from multiple sellers for a specific 341 use, specifically Endangered Species Act (ESA) needs in the Klamath River. The amount of water 342 acquired during each water bank program was based on the estimate of the water demand 343 reduction needed in order to meet delivery objectives and ESA requirements. 344 345 During the water bank programs, up to three water management strategies were utilized to 346 decrease Project demand and provide additional water supplies: 1) cropland idling/dryland 347 farming, 2) groundwater substitution (direct and indirect), and 3) storage. Water bank 348 programs changed from year to year based on demand, and lessons learned through the 349 implementation of water management strategies. 350 351 The official name of each water bank program for a specific year, along with the facilitating 352 entity are identified in Table 2-2.

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353 354 Table 2-2. Official name of water bank program.

Year Official Name of Water Bank Program Facilitating Entity Pilot Irrigation Demand Reduction Program (Cropland Idling) 2001 Reclamation Groundwater Acquisition Program (Groundwater Substitution) 2002 No Program Reclamation

2003 Klamath Basin Pilot Water Bank Reclamation

2004 Klamath Basin Pilot Water Bank Reclamation

2005 Klamath Basin Pilot Water Bank Reclamation

2006 Klamath Basin Pilot Water Bank Reclamation

2007 Water Supply Enhancement Study Reclamation

2008 No Program KWAPA

2009 No Program KWAPA

2010 Water User Mitigation Program (WUMP) KWAPA

2011 No Program KWAPA

2012 Water User Mitigation Program (WUMP) KWAPA

2013 Water User Mitigation Program (WUMP) KWAPA

2014 Water User Mitigation Program (WUMP) KWAPA

2015 Water User Mitigation Program (WUMP) KWAPA

2016 No Program KWAPA

2017 No Program Reclamation

2018 Groundwater Program & Land Idling Program KPDRA

2019 No Program KPDRA

2018 Groundwater Program & Land Idling Program KPDRA 355 356 2.1.3 Land Use Elements or Topic Categories of Applicable General Plans (Reg. § 354.8 f)

357 The Subbasin is located within Modoc County and Siskiyou County, which have jurisdiction over 358 land use planning. Implementation of the GSP will be affected by the policies and regulations

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359 outlined by the Modoc County General Plan and Siskiyou County General Plan given that the 360 long-term land use planning decisions that would affect the Subbasin are under the jurisdiction 361 of Modoc County and Siskiyou County. In addition, the implementation of these plans may 362 change water demands in the Subbasin, may influence the GSP’s ability to achieve sustainable 363 groundwater use. Additionally, the GSP may affect implementation of the land use policies 364 outlined in these plans. 365 366 2.1.3.1 Modoc County General Plan

367 The Land Use Element of the General Plan prepared by Modoc County identifies policies and an 368 action program to meet the primary goal to protect and support the agricultural economy of 369 Modoc County. 370 371 2.1.3.2 Siskiyou County General Plan

372 The County of Siskiyou General Plan (General Plan) serves as a guide for land use decisions 373 within Siskiyou County (the County), ensuring alignment with community objectives and 374 policies. While the General Plan does not prescribe land uses to parcels of land, it does identify 375 areas that are not suitable for specific uses. The components of the General Plan with the most 376 relevance to the GSP include the Conservation Element and Open Space Element. Many of the 377 objectives and policies within the General Plan align with the aims of the GSP and significant 378 changes to water supply assumptions within these plans are not anticipated. 379 The Conservation Element of the General Plan (County of Siskiyou 1973) recognizes the 380 importance of water resources in the County and outlines objectives for the conservation and 381 protection of these resources to ensure continued beneficial uses for people and wildlife. 382 Methods for achieving these objectives include local legislation such as flood plain zoning and 383 mandatory setbacks, subdivision regulations, grading ordinances and publicly managed lands to 384 ensure preservation of open spaces for recreational use. The importance of water resources is 385 clearly noted: “Groundwater resources, water quality and flood control remain the most 386 important land use determinants within the county” (County of Siskiyou 1973). Specific topics 387 addressed include: preventing pollution from industrial and agricultural waste, maintaining 388 water supply and planning for future expansion, reclaiming and recycling wastewater and 389 protecting watershed or recharge lands from development. These objectives in the 390 Conservation Element mirror the objectives of the GSP, namely ensuring a sustainable water 391 supply, the protection and preservation of watershed and water recharge lands and prevention 392 of degradation of water quality. 393 The Open Space Element of the General Plan includes, in its definition of open space, 394 watershed and groundwater recharge land (County of Siskiyou 1972). The importance of

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395 protecting these lands is recognized for maintaining water quality and quantity. Mechanisms to 396 preserve these spaces include maintaining or creating scenic easement agreements, preserves, 397 open space agreements and designation of lands for recreational or open space purposes. A 398 policy for open space requirements is included with minimum thresholds of 15% of proposed 399 developments as open space. Protection of open space for habitat, water quality and water 400 quantity align with the objectives of the GSP. 401 Siskiyou County Zoning Plan 402 The Siskiyou County Zoning Plan (Zoning Plan) is codified in Title 10 (DWR, n.d.). Chapter 6 of 403 the County Code. The Siskiyou County Zoning Ordinance outlines the permitted types of land 404 use within each zoning district. Zoning categories include residential, commercial, industrial, 405 agricultural, forestry, open space and flood plains. Many of the purposes and policies of the 406 Zoning Plan align with the objectives of the GSP. In particular, the “wise use, conservation, 407 development and protection” of the County’s natural resources, protection of wildlife and 408 prevention of pollution support the objectives of the GSP. Mechanisms to achieve these goals 409 include permitted and restricted uses for land parcels, requirements and stipulations for land 410 use and development. 411 412 2.1.3.3 Land Use Plans Outside the Subbasin

413 As identified in Section 2.1.1.1, the Subbasin is located within the southeastern region of the 414 Upper Klamath Basin Klamath. Adjacent to the northern boundary of the Subbasin is Klamath 415 County. A comprehensive plan for Klamath County was prepared and identifies an agricultural 416 land primary objective of economically stabilizing the agricultural community in Klamath 417 County. Land use decisions in Klamath County are likely to effect groundwater conditions in the 418 Subbasin, which is why the GSAs included a Core Team Advisory Member from Klamath County. 419 420 2.1.3.4 Groundwater Sustainability Plan Implementation

421 Because the Subbasin is already operated sustainably [need to verify once water budgets are 422 prepared], implementation of this GSP will not change water demands nor water supply 423 assumptions of the land use plans previously identified. 424 425 2.1.4 Additional GSP Elements (Reg. § 354.8 g)

426 The following topics are required to be addressed in the GSP. The references for each topic 427 have also been included. 428 • Control of saline water intrusion

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429 o See Section X for an explanation as to why the saline water intrusion 430 sustainability indicator does not apply to the Subbasin. 431 • Wellhead protection 432 o See information provided under Section 2.1.2.9 “County Ordinances and 433 Permitting”. 434 • Migration of contaminated groundwater 435 o See Section X for details on migration of contaminated groundwater. 436 • Well abandonment and well destruction program 437 o See information provided under Section 2.1.2.9 “County Ordinances and 438 Permitting”. 439 • Replenishment of groundwater extractions 440 o See Section X for details on groundwater extractions. 441 • Conjunctive use and underground storage 442 o See Section X for details on conjunctive use and underground storage, and see 443 information provided under Section 2.1.2.1 “Groundwater Management Plan 444 (2013)”. 445 • Well construction policies 446 o See information provided under Section 2.1.2.9 “County Ordinances and 447 Permitting”. 448 • Groundwater contamination cleanup, recharge, diversions to storage, conservation, 449 water recycling, conveyance, and extraction projects 450 o See Section X for details on projects. 451 • Efficient water management practices 452 o See information provided under Section 2.1.2.2 “Agricultural Water 453 Management Plan (2017)”. 454 • Relationships with state and federal regulatory agencies 455 o See Section X for details on relationships with state and federal regulatory 456 agencies. 457 • Land use plans and efforts to coordinate with land use planning agencies to assess 458 activities that potentially create risks to groundwater quality or quantity 459 o See information provided under Section 2.1.3. 460 • Impacts on groundwater dependent ecosystems 461 o See Section X for details on groundwater dependent ecosystems. 462 463 2.1.5 Notice and Communication (Reg. § 354.10)

464 See Appendix C for the GSAs Communications and Engagement Plan, which includes details on 465 the GSAs decision making process, goals, stakeholder identification process, venues for

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466 engagement, and implementation timeline. Appendix C also includes comments received 467 regarding the GSP, a list of the meeting held to date, a list of the advisory team members, and a 468 list of the interested persons.

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1 2.2 Basin Setting 2 The following section provides a brief background of the geology and hydrology of the Upper 3 Klamath Basin and the portion of the Upper Klamath Basin that is covered by the GSP area 4 (Tulelake Subbasin). 5 6 2.2.1 Hydrogeologic Conceptual Model (Reg. § 354.14)

7 This Hydrogeologic Conceptual Model (HCM) is prepared pursuant to California Code of 8 Regulations Section 344.12. In general, this follows the description of the Tulelake Subbasin 9 prepared by the Department of Water Resources (DWR) for the 2003 update to Bulletin 118. 10 11 2.2.1.1 Basin Boundaries and Hydrology

12 The Upper Klamath Groundwater Basin is approximately 8,000 square miles and is located in 13 south central Oregon and northeastern California on the east side of the Cascade Mountain 14 Range. Figure 2-1 identifies the location of the Upper Klamath Groundwater Basin. As further 15 described in this section, the Tulelake Subbasin (Subbasin) is located in the southeastern 16 portion of the Upper Klamath Basin. 17 18 The Subbasin is bounded to the west by the Gillems Bluff Fault which extends beneath and is a 19 major structural feature of the Medicine Lake volcanic highlands (Lavine 1994). The fault forms 20 the steep eastern escarpment of Sheepy Ridge, which separates the Tulelake and Lower 21 Klamath subbasins (DWR, 2003b). The basin boundary extends to the fault-controlled drainage 22 divide between the Tulelake and Lower Klamath Lake subbasins (the crest of Sheepy Ridge). 23 Volcanic deposits extend eastward from the crest beneath the Quaternary sediment, and are 24 penetrated by wells, which are producing from the volcanic deposits on the west margin of the 25 basin (Gannett, 2016). 26 27 The Subbasin is bounded to the east by the Saddle Blanket Fault Zone, a north-trending normal 28 fault, which forms the western edge of the block faulted mountains between Tulelake and Clear 29 Lake Reservoir. The Subbasin extends to a portion of the Quaternary volcanic deposits which 30 includes irrigation wells (Gannett et al., 2007). Clear Lake Reservoir is the headwaters of Lost 31 River. Lost River flows north into Oregon, and meanders through the Poe and Langell valleys 32 before it flows south into California, and ends at the Tulelake sump (DWR, 2003b). 33 34 The Subbasin is bounded to the south by the low-lying volcanic fields on the north slope of the 35 Medicine Lake Highlands. Medicine Lake occupies the crater at the peak of this large, relatively

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36 young shield volcano. The Subbasin includes the Peninsula and extends to the east to the 37 Saddle Blanket Fault Zone. Wells in these areas where the volcanics are exposed, mostly 38 produce from the surficial volcanic deposits, but some wells penetrate through the surficial 39 deposits and underlying basin-filling sediments to the underlying volcanic strata (Gannett, 40 2016). 41 42 To the north, the basin extends into Oregon and is bounded by northwest trending normal 43 faults on the south side of the mountain block dividing Poe Valley from the Tulelake Subbasin. 44 Approximately two-thirds of the Subbasin are in California. For the purposes of this Basin’s 45 Boundary Modification and the Sustainable Groundwater Management Act (SGMA), the 46 Subbasin is bounded to the north by the state boundary of Oregon and California. 47 48 A map of the Tulelake Subbasin is provided as Figure 2-9. 49

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50 51 Figure 2-9. Tulelake Subbasin Boundary 52

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53 Figure 2-4 identifies the Klamath Project surface water bodies and conveyance facilities that are 54 significant to the management of the Subbasin. Figure 2-5 identifies surface water bodies and 55 conveyance facilities within the District, which are significant to the management of the 56 Subbasin. 57 58 A map identifying the soil characteristics of the Tulelake Subbasin is provided as Figure 2-10. 59

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60 61 Figure 2-10. Tulelake Subbasin Soil Characteristics 62

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63 A topographic map of the Tulelake Subbasin is provided as Figure 2-11.

64 65 Figure 2-11. Tulelake Subbasin Topography

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66 67 2.2.1.2 Hydrogeologic Information

68 Water-Bearing Formations. The principal water-bearing formations in the subbasin include 69 Tertiary to Quaternary lake deposits and volcanics. In general, two major aquifer systems have 70 been identified in the Subbasin. They are the alluvial aquifer system and the volcanic aquifer 71 system. The alluvial aquifer system consists of the surficial deposits that extend to over 1,000 72 feet deep in the center of the basin. The volcanic aquifer system consists of the Upper, 73 Intermediate, and Lower basalt units, as well as pyroclastic and tuffaceous deposits. 74 Groundwater in the surficial deposits and Upper Basalt is unconfined. The Intermediate Basalt 75 and scoraceous deposits are predominantly unconfined in the southern portion of the basin 76 where they exist at or near the surface and become confined as they deepen beneath the lake 77 sediments in a northward direction. The Lower Basalt is confined in the center of the basin 78 where it underlies surficial deposits, but is unconfined or semi-confined where it crops out at 79 the edges of the basin. The tuffaceous deposits are predominantly confined except where they 80 crop out on the west side of the Subbasin and on portions of the Peninsula (DWR, 2003a). 81 82 Pliocene to Miocene Lower Basalt. This Lower Basalt is a primary water-bearing deposit for 83 irrigation, public, and municipal wells. The older basalt ranges from green black ophitic olivine 84 basalt to a gray-black porphyritic basalt. It often exhibits weak columnar jointing and fracturing 85 in surface exposures. This is typically a highly permeable aquifer that is commonly confined 86 within the Subbasin where it underlies lake sediments (DWR, 2003b). At the edges of the basin 87 at the north, east, and west, the Lower Basalt acts more unconfined or semi-confined (DWR, 88 2003a). Where volcanic rocks are exposed at the surface, the area probably is underlain by an 89 unconfined aquifer body (Hotchkiss, 1968). Surface exposure of the unit occurs east and west 90 of the Subbasin. For the purposes of sustainable groundwater management and based on 91 known areas of groundwater use, the unconfined aquifer of the Lower Basalt is assumed to 92 extend to the east where surface exposure occurs. Review of hydrographs show that these 93 wells reflect similar stresses to wells located throughout the Tulelake Subbasin, which indicates 94 a hydrogeologic connection and possible interbedding of basalt layers with lake deposits 95 (Gannett, 2016; DWR, 2003a). Where exposed in the uplands surrounding the basin, the unit is 96 an important source of recharge. 97 98 The depth to the older basalt beneath the lake sediments varies due to the region's extensive 99 block faulting. New deep irrigation wells drilled in 2001 on the California/Oregon border show 100 that the basalt is encountered at depths ranging from 810 feet on the east side of the basin to 101 1,190 feet several miles to the west, and to 190 feet on the far west side. These differing 102 depths probably represent individual blocks offset by steep, normal faults. The Lower Basalt 45

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103 can yield large quantities of water suitable for irrigation purposes (DWR, 2003a). The depth to 104 good production zones in these wells varies from 800 feet to 1,200 feet to 245 feet in the same 105 east to west order. On the east side of the Subbasin well yields range from 4,000- to 7,000-gpm, 106 whereas, yields mid-basin and on the west side range from 9,000- to 12,000-gpm (DWR, 107 2003b). 108 109 Pleistocene Intermediate Basalt. This unit is a series of reddish brown to black, thin bedded 110 flows of Pleistocene diabasic olivine basalt. These rocks border the surficial alluvium to the 111 south and east and interfinger with lakebed deposits at the edge of the basin. These rocks are 112 generally highly permeable due to well-developed columnar jointing and the abundance of 113 bedding planes. Wells developed in these rocks will often yield moderate to large quantities of 114 water ranging from 2,000- to 4,000-gpm with specific capacities of 50- to 250-gpm per foot of 115 drawdown if sufficient fractures, fracture interconnections, and saturated depths are 116 encountered (Hotchkiss, 1968). 117 118 This unit is exposed at the surface in the southern portion of the Subbasin and crops out on the 119 eastern and western ridges (DWR, 2003a). Along the southern edge, this Quaternary basalt 120 overlies and is interbedded with basin-filling sediments (Gannett, et al., 2012). This is evidenced 121 in the Peninsula region and southeast of Copic Bay where groundwater pumping occurs for 122 irrigation. Analysis of available hydrographs indicates that groundwater levels in this area 123 reflect similar stresses as those seen elsewhere in the basin, suggesting that the surficial basalt 124 and deeper volcanics are in hydraulic connection (Gannett, 2016). 125 126 Some well yields in this unit are low where extensive cross faulting has created barriers to 127 groundwater recharge and flow. In the Panhandle region, the thickness of the unit is greater 128 than 400 feet with well yields ranging up to 9,500 gpm with specific capacity up to 395 gpm per 129 foot of drawdown. In the vicinity of Prisoners Rock and the Peninsula, the unit reaches a 130 thickness of at least 400 feet with estimated well yields of 500- to 3,100-gpm (DWR, 2003b). 131 132 Pleistocene Upper Basalt. This unit is an unweathered, vesicular, olivine basalt that is generally 133 highly permeable due to extensive fracturing. The basalt flows of this unit are generally above 134 the saturated zone in upland areas, but serve as recharge areas where fractured. Some areas 135 have exposures of massive, unfractured flows. The fractured flows readily yield water to wells. 136 These flows border the Subbasin on the south (to the west of the Peninsula), and outcrop as a 137 Subbasin boundary to the southeast of Copic Bay along the north flank of the Medicine Lake 138 Highlands (DWR, 2003b). 139

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140 Pliocene to Holocene Lake Deposits. The surficial deposits, consisting mostly of fluvial and 141 lacustrine sediments are unconsolidated to semi-consolidated (DWR, 2003a). The lake deposits 142 consist of sand, silt, clay, ash, lenses of diatomaceous earth, and semi-consolidated shale. 143 Poorly sorted deposits have very low permeability and may act as a confining layer where 144 interfingered with basalts. Wells developed in the sedimentary deposits are usually less than 145 150 feet deep, and yield only small quantities of water in the range of 30 gpm (Hotchkiss 1968). 146 Isotopic analysis of groundwater in aquifers supplying deep irrigation wells in the Subbasin 147 suggest a hydraulic connection between the shallow (alluvial) aquifer and deep (volcanic) 148 aquifer (Pischel and Gannett, 2015). 149 150 2.2.1.3 Restrictive Structures

151 The western boundary of Tulelake is marked by a prominent north-south trending normal fault, 152 downthrown to the east. The displacement is unknown, but is probably in the range of several 153 hundred feet. The east side of the Tulelake Subbasin is bounded by a normal fault downthrown 154 to the west. Subsurface block faulting can also cause boundaries or conduits to groundwater 155 flow. It is assumed a buried horst may exist, extending from Turkey Hill in the north to the 156 Peninsula to the south (DWR, 2003a). 157 158 The water-transmitting properties of these faults are not fully understood. 159 160 2.2.1.4 Bottom of Subbasin

161 The volcanic units of the Subbasin comprise the bedrock and produce groundwater through 162 fractures and voids. In locations throughout the Subbasin, the volcanic units may be 163 interbedded with basin fill deposits (DWR 2003a). Due to the interaction between the volcanic 164 aquifer and alluvial aquifer, it is difficult to define the bottom of the Subbasin. 165 166 A review of cross sections incorporated into USGS models identifies the bottom of the basin at 167 approximately 1,500-2,000 feet above mean sea level (Gannett, et al., 2012; Wagner and 168 Gannett, 2014). This corresponds to the assumed location of contact between the regional 169 groundwater flow system and underlying rock with very low permeability (Gannett, et al., 170 2012). Figure 2-12 identifies the location of the cross sections and Figure 2-13 provides the 171 cross sections. 172

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Cross Sections Shown in Figure 2-13

173 174 Figure 2-12. Hydrologic Units of the Upper Klamath Basin, Oregon and California 175

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176 177 Figure 2-13. Series of west-to-east geologic cross sections through the central part of the Upper Klamath Basin. 178 179 The findings by the USGS correlate to cross sections developed by DWR which identify 180 interbedded volcanics and fill deposits occurring at varying depths (DWR, 2003a). The location 181 of the DWR cross sections are identified in Figure 2-14 and the DWR, cross sections are 182 provided in Figure 2-15.

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183 {Insert Figure 2-14 Geologic Map of the Tulelake Subbasin}

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184 {Insert Figure 2-15 Cross Sections of the Tulelake Subbasin}

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185 The location and quantity of groundwater movement, including migration and recharge within 186 any groundwater basin is difficult to quantify, as there are various factors that affect each of 187 the components. In many cases, limited data regarding one aspect of the movement of 188 groundwater can make it difficult to develop a comprehensive understanding of the 189 groundwater basin. In order to better understand groundwater in the Upper Klamath Basin, a 190 groundwater simulation and management model (Model) was developed by the USGS, in 191 collaboration with Oregon Water Resources Department, and Reclamation. This Model provides 192 improved understanding of how groundwater and surface‐water system responds to varying 193 hydrologic conditions and groundwater pumping within the Upper Klamath Basin. In order to 194 develop this Model, the USGS relied on countless reports compiled within the Upper Klamath 195 Basin relative to surface and groundwater. One of these reports, titled Ground‐water Hydrology 196 of the Upper Klamath Basin, Oregon and California (Gannett et al., 2007) describes that 197 groundwater flow in the Upper Klamath Basin is influenced by topography, geologic 198 composition, stream system geometry, recharge of precipitation and applied water, and 199 groundwater production from wells. The groundwater flow system receives large amounts of 200 recharge from deep percolation of precipitation, snowmelt in the Cascades Range, and upland 201 areas within and on the eastern margins of the basin. The primary components of groundwater 202 discharge include discharge to streams through a complex of springs within the Upper Klamath 203 Basin interior, and discharge to wells at various locations and depths. Groundwater in the 204 Upper Klamath Basin generally flows toward Upper Klamath Lake, the Klamath River Canyon, 205 and the Tulelake Subbasin (see Figure 2-16; Gannett et al., 2007).

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206 207 Figure 2-16. Generalized Water‐Level Contours and Approximate Directions of Regional Groundwater 208 Flow within the Upper Klamath Basin, Oregon and California 209

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210 2.2.1.5 Recharge Areas

211 Local precipitation and infiltration of surface water from the channels, lakes, and sumps of the 212 Lower Klamath and Tulelake Subbasins provide recharge for the alluvial aquifer system. Water 213 levels in the alluvial aquifer fluctuate seasonally in response to canal and irrigation operations 214 (DWR, 2003a). Surface water supplies available to the Tulelake Irrigation District provide an 215 unknown amount of groundwater recharge. These surface water supplies include natural flow 216 from the Klamath River, stored water from Upper Klamath lake and Lake Ewauna, return flows 217 from upstream irrigation, and flow from the Lost River. 218 219 Underflow from the adjacent, rapidly-replenished volcanic rocks are probably the principal 220 sources of recharge in this basin. Because infiltration rates are very slow in the sedimentary 221 deposits, underflow from adjacent volcanics is probably of major significance (DWR, 2003b). 222 Where the volcanic units are at or near the surface and are unconfined, water can percolate 223 into fractures and vesicles that lead to lower units (DWR, 2003a). The area surrounding this 224 basin, and its extension into Oregon, primarily consists of Holocene to Miocene volcanic rocks 225 that capture most of the incipient precipitation and intermittent streamflow by infiltration 226 through fractures. Within the Tulelake Subbasin, the exposed volcanic recharge areas are 227 between the surficial alluvium and the boundaries of the basin at the eastern and western 228 edges. These rocks probably function as a single, continuous, water-table aquifer that extends 229 across faults and surrounds the basin. Hence, the two principal sources of recharge are: 230 underflow from the rapidly replenished and permeable unconfined system of the adjacent 231 volcanic rocks; and less significantly, the very-slow vertical infiltration of surface water through 232 marginally permeable sedimentary deposits (DWR, 2003b). The general pattern of groundwater 233 movement is from the north to the south. 234 235 During the development of the Model, the quantity and location of groundwater recharge was 236 estimated within the Upper Klamath Basin, based on representative parameter values applied 237 to the Model. Figure 2-17 identifies the estimated quantity and distribution of recharge in the 238 Upper Klamath Basin, Oregon and California. The average annual recharge from precipitation is 239 estimated to be approximately 2.6 million acre‐feet per year within the Upper Klamath Basin 240 (Gannett et al., 2012). 241

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242 243 Figure 2-17. Estimated Mean Annual Groundwater Recharge from Precipitation in the Upper Klamath 244 Basin, Oregon and California, 1970‐2004, in inches, and Recharge Parameter Zones 245 246 2.2.1.6 Discharge

247 Aquifer discharge occurs when groundwater is extracted by wells, discharges to streams, 248 evapotranspired by phreatophytes, or flows out of the groundwater basin in the subsurface

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249 (DWR, 2003a). Most groundwater production in the Tulelake Subbasin is from the underlying 250 volcanic strata, volcanic deposits on the periphery of the basin, and volcanic deposits that 251 partly overlie basin-filling sediment in the Peninsula area. However, wells in any of these areas 252 may produce from surficial volcanic deposits, basin filling sediments, or underlying volcanic 253 strata (Pischel and Gannett, 2015). In general, inter-basin groundwater flow from the Tulelake 254 Subbasin is southward (Gannett, et al., 2007). 255 256 The primary components of groundwater discharge include discharge to streams through a 257 complex of springs within the Upper Klamath Basin interior, and discharge to wells at various 258 locations and depths. Groundwater in the Upper Klamath Basin generally flows toward Upper 259 Klamath Lake, the Klamath River Canyon, and the Tulelake Subbasin (Figure 2-16; Gannett et 260 al., 2007). 261 262 2.2.1.7 HCM Data Gaps

263 The HCM was collaboratively developed by multiple entities using the best available data. As 264 appropriate, new data collected via the program, identified in Section 2.1.2, will be 265 incorporated into the HCM for future GSP updates. 266 267 References

268 California Department of Conservation, Division of Mines and Geology. 1966. Geology of 269 Northern California. California Department of Conservation, Division of Mines and Geology. 270 Bulletin 190. 271 California Department of Water Resources. 1960. Northeastern Counties Investigation. 272 California Department of Water Resources. Bulletin 58. 273 California Department of Water Resources. 1964. Klamath River Basins Investigation. 274 California Department of Water Resources. Bulletin 83. 275 California Department of Water Resources. 1975. California's Ground Water. California 276 Department of Water Resources. Bulletin 118. 277 California Department of Water Resources. 1980. Ground Water Basins in California. 278 California Department of Water Resources. Bulletin 118-80. 279 California Department of Water Resources. 2003a. Tulelake Subbasin—Hydrogeologic 280 investigation. California Department of Water Resources Draft Report. 281 California Department of Water Resources. 2003b. California’s Groundwater: California 282 Department of Water Resources Bulletin 118 (update 2003). 283 Gannett, M.W., et al. 2007. Ground-Water Hydrology of the Upper Klamath Basin, Oregon and 284 California. U.S. Geological Survey Scientific Investigations Report 2007 – 5050.

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285 Gannett, M.W., et al. 2012. Groundwater Simulation and Management Models for the 286 Upper Klamath Basin, Oregon and California. U.S. Geological Survey Scientific Investigations 287 Report 2012–5062. 288 Gannett, M.W. 2016. Personal communication. U.S. Geological Survey. 289 Gay, T.E., Jr., and Aune, Q.A. 1958. Geologic Map of California, Olaf P. Jenkins edition, 290 Alturas Sheet. California Division of Mines and Geology, Scale 1:250,000. 291 Hotchkiss WR. August 1968. A Geologic and Hydrologic Reconnaissance of Lava Beds 292 National Monument, California. USGS. Survey Open-File Report, 30p. 293 Lavine A. 1994. Geology of Prisoners Rock and The Peninsula: Pleistocene 294 Hydrovolcanism in the Tulelake Basin, Northeastern California. California Geology 47(4):95-103. 295 Pischel, E.M., and Gannett, M.W. 2015. Effects of Groundwater Pumping on Agricultural Drains 296 in the Tulelake Subbasin, Oregon and California. U.S. Geological Survey Scientific Investigations 297 Report 2015–5087. 298 Wagner, B.J., and Gannett, M.W. 2014. Evaluation of Alternative Groundwater Management 299 Strategies for the Bureau of Reclamation Klamath Project, Oregon and California. U.S. 300 Geological Survey Scientific Investigations Report 2014–5054.

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1 2.2.2 Current and Historical Groundwater Conditions (Reg. § 354.16)

2 The main source of water within the Subbasin is surface water from the Klamath River. 3 The water is made available to the District from the Klamath Reclamation Project for 4 irrigation purposes through an intertie between the Klamath River and the Lost River. 5 The District also receives tailwater from Klamath River water users located north of the 6 California-Oregon Stateline. At times, the Lost River provides some surface water to the 7 District. For uses other than irrigation, and to meet irrigation demands when not 8 enough surface water supply is available, groundwater is pumped to meet water 9 demands. Groundwater levels within the Subbasin fluctuate partially as a result of the 10 amount of surface water delivered to the District. 11 12 In 2001, the District constructed 10 groundwater wells to provide supplemental water 13 supplies during dry years. The District only operated these wells during dry years and 14 generally represents a small portion of the total water supply in a given year. However, 15 landowners within the District may operate private wells at any time. Beginning in 16 2001, reduction in available surface water supplies resulted in an increase in 17 groundwater extraction. 18 19 Larger scale pumping in the Subbasin has been due to participation in water bank 20 programs during years where surface water supplies have been limited. DWR has 21 estimated that groundwater pumping during the 2001 through 2009 period ranged from 22 approximately 10,000 acre-feet to 70,000 acre-feet within the Subbasin (DWR, 2011). 23 Similar programs were also established in 2012, 2013, 2014, 2015, 2018 and 2020. This 24 pumping estimate includes the 8,500 acre-feet of estimated pumping for domestic, 25 stockwatering, and municipal supplies. 26 27 2.2.2.1 Historic Groundwater Elevations

28 Groundwater elevation data has been collected by DWR and the USGS beginning in the 29 1980’s within the GSP area. Prior to 1999, DWR monitored groundwater elevations in 30 five wells twice each year (spring and fall). In 1999, an expanded groundwater 31 monitoring program was developed through a contract with Reclamation to increase 32 the monitoring well network from five wells to thirty five (35) wells. By the mid 2000’s 58

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33 the monitoring well network had expanded to an average of seventy (70) wells 34 monitored on a monthly basis within the Subbasin and an adjacent subbasin (the Lower 35 Klamath Subbasin). 36 37 The groundwater elevation data collected by DWR and other entities, including the 38 District is uploaded to the DWR Water Data Library (WDL). Table 1 identifies the State 39 Well Number (SWN), location, depth, depth of perforations, use type, and period of 40 monitoring of the approximately 70 wells monitored within the Subbasin. 41 42 Table 1. Wells monitored for groundwater elevations within and near the GWMP area

State Well Well Location Well Perforations (ft) Well Period of Record Number UTM East UTM North Depth (ft) Top Bottom Use Begin End 48N05E36K001M 636857 4646373 66 21 66 Stock 11/9/2001 Present 48N05E36A002M 637472 4646826 528 - - Irrigation 9/16/1998 Present 48N05E35F001M 634950 4646522 32 25 32 Domestic 8/22/1987 Present 48N05E33H001M 632533 4646676 57 - - Irrigation 9/10/1998 Present 48N05E26D001M Present 634823 4648412 1810 1250 1802 Irrigation 9/12/2001 (TID Well No. 8) 48N05E25Q002M 637118 4647239 - - - Domestic 11/9/2001 10/25/2017 48N05E24P001M 636676 4649183 112 - - Domestic 9/9/1998 Present 48N05E22L001M 633295 4649188 65 - - Stock 9/10/1998 Present 48N05E22H001M 634129 4649916 203 36 203 Irrigation 7/23/2002 8/27/2013 48N05E16P001M Present 631643 4650575 2600 823 2358 Irrigation 8/10/2001 (TID Well No. 6) 48N05E14R001M Present 635760 4650660 2030 814 2020 Irrigation 8/16/2001 (TID Well No. 7) 48N05E13R003M 637344 4650713 - - - Domestic 4/25/2002 3/25/2014 48N04E35C001M 625776 4646739 2790 2561 2761 Municipal 12/22/2003 Present 48N04E35G001M 626538 4646542 220 - - Irrigation 8/13/1998 Present 48N05E36D001M Present 636270 4647161 2043 - - Irrigation 9/05/2001 (TID Well No. 9) 48N04E31N002M 618801 4645596 337 292 337 Domestic 10/17/1995 Present 48N04E31M001M 618885 4645689 40 - - Domestic 8/20/1998 Present 48N04E30F004M 619471 4647993 - - - Domestic 11/7/2001 Present 48N04E30F002M Present 619583 4647681 740 260 700 Irrigation 6/27/2001 (TID Well No. 1) 48N04E30F001M 619526 4647740 142 - - Industrial 8/20/1998 Present 48N04E30E001M 619060 4647474 185 19 185 Domestic 9/30/1998 4/27/2011 48N04E30C002M 619503 4648378 84 69 74 Domestic 11/2/2001 Present 48N04E28D001M 622541 4648128 140 - - Irrigation 8/20/1998 Present 48N04E22M001M 623798 4649129 135 31 135 Domestic 11/8/2001 Present

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State Well Well Location Well Perforations (ft) Well Period of Record Number UTM East UTM North Depth (ft) Top Bottom Use Begin End 48N04E19C001M 619377 4649996 38 22 38 Domestic 11/7/2001 Present 48N04E18L003M 619372 4650598 110 98 110 Domestic 8/19/1998 Present 48N04E18J001M Present 620463 4650579 1550 1260 1540 Irrigation 8/27/2001 (TID Well No. 2) 48N04E17C001M 621254 4650589 159 89 129 Domestic 11/8/2007 Present 48N04E16M001M Present 622152 4650599 1710 1053 1681 Irrigation 8/16/2001 (TID Well No. 3) 48N04E16L002M 623088 4650624 150 50 150 Industrial 8/1/1998 Present 48N04E15K001M Present 624805 4650629 1440 1212 1433 Irrigation 8/10/2001 (TID Well No. 4) 48N04E14M001M 625532 4650579 127 - - Stock 9/16/1998 Present 48N04E13K001M Present 628217 4650610 1570 935 1557 Irrigation 8/12/2001 (TID Well No. 5) 48N03E34N001M 614107 4645584 262 - - Stock 9/1/1998 Present 48N03E14M001M 615964 4650542 454 - - Irrigation 9/11/1998 11/23/2009 48N02E14J001M 607580 4650361 203 21 200 Domestic 8/17/1998 2/25/2010 47N06E30H001M 639048 4638513 680 198 650 Irrigation 9/15/1998 Present 47N06E19D002M 637956 4640502 245 - - Irrigation 9/3/1998 Present 47N06E06N002M 637707 4644032 1575 - - Irrigation 9/3/1998 Present 47N06E06N001M 637714 4644033 85 - - Irrigation 9/3/1998 Present 47N05E33F001M 631976 4637066 54 - - Industrial 8/18/1998 Present 47N05E26F001M 635184 4638313 105 78 98 Irrigation 8/18/1998 Present 47N05E04M001M 631148 4644392 71 68 72 Industrial 10/28/1987 Present 47N05E01N001M 636509 4643988 65 49 65 Domestic 10/28/1987 Present 47N05E01H001M 637501 4644971 1000 - - Stock 3/18/1999 Present 47N04E07Q001M 619097 4642356 1170 146 289 Irrigation 9/2/1998 Present 46N06E08E001M 639424 4633481 213 - - Irrigation 9/8/1998 Present 46N06E07K002M 638839 4633192 101 - - Domestic 9/8/1998 Present 46N05E24P002M 636799 4629838 188 140 188 Irrigation 8/18/1998 Present 46N05E23G002M 635418 4630333 209 150 190 Irrigation 8/14/1998 Present 46N05E22D001M Present 633266 4630751 571 114 554 Irrigation 7/31/2001 (TID Well No. 14) 46N05E21M001M 631682 4630060 325 32 100 Irrigation 7/24/2002 Present 46N05E21J001M 632719 4630034 32 - - Domestic 11/9/2001 Present 46N05E16N001M 631419 4631249 - - - Domestic 11/9/2001 10/31/2018 46N05E09J003M 632842 4633205 132 - - Industrial 8/18/1998 Present 46N05E03P001M 633424 4634509 173 10 89 Monitoring 9/3/1998 Present 46N05E03M003M 633203 4634749 - - - Irrigation 7/23/2008 Present 46N05E03M002M 632965 4635144 252 - - Irrigation 9/4/1998 Present 46N05E03M001M 632976 4635138 126 - - Irrigation 9/4/1998 Present

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State Well Well Location Well Perforations (ft) Well Period of Record Number UTM East UTM North Depth (ft) Top Bottom Use Begin End 46N05E01P001M 636763 4634300 101 87 101 Domestic 10/25/1994 Present 46N05E01B001M 636943 4635559 140 - - Irrigation 5/24/2001 Present 41S12E23H001W 634935 4651610 150 - - Industrial 11/9/2001 Present 41S12E22Q001W 632785 4650754 600 - - Industrial 11/8/2001 Present 41S12E21Q001W 631062 4651080 - - - Domestic 11/8/2001 Present 41S12E19Q001W 627992 4650692 65 - - Domestic 11/8/2001 Present 41S12E16J001W 631556 4652891 380 - - Municipal 11/8/2001 Present 41S12E15M002W 631946 4652420 84 - - Municipal 11/8/2001 9/4/2019 41S11E16R002W 622342 4650776 70 - - Industrial 8/28/2002 Present 41S11E16R001W 622046 4650694 70 - - Domestic 11/8/2001 Present TL-T3 GP 627056 4633043 500 - - Monitoring 1/10/2011 Present TL-T1 Q3B 621062 4632384 500 - - Monitoring 1/10/2011 Present Note: Information was obtained from DWR’s Water Data Library. As additional information becomes available, this table will be updated. 43 44 Figure 2-19 identifies the distribution of groundwater wells actively monitored for 45 groundwater elevations within and near the GSP area. The wells shown on this figure 46 include groundwater wells drilled to depths such that extraction may occur from the 47 alluvial aquifer or from the deeper, more productive volcanic aquifer. For the purposes 48 of this GSP, wells that most likely pump from the alluvial aquifer (those with shallow 49 perforation and depths less than 500 feet) are described as “shallow groundwater 50 wells”. Wells with depths greater than 500 feet and deep perforations most likely pump 51 from the deeper volcanic aquifer and are described as “deep groundwater wells”. Well 52 depth and construction information, including perforations are not available for all 53 groundwater wells monitored for elevations within the GSP area. Some wells with 54 unknown depths are also shown on Figure 2-19.

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55 56 Figure 2-19. Wells monitored for groundwater elevations within and near the GSP area 57 The reduction in available surface water supplies beginning in 2001 has resulted in an 58 increase in groundwater extraction within the Klamath Reclamation Project, including 59 the GSP area. As a result, recent trends in groundwater elevation are reflective of not 60 only climatic conditions and surface water recharge, but also the generally increased, 61 although varying, levels of annual groundwater extraction. Figure 2-20 identifies the 62 location of the wells where groundwater elevation data was reviewed and represented 63 in hydrographs (Figures 2-21 through 2-29) as further described below. 64 65

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66 67 Figure 2-20. Wells monitored for groundwater elevations within and near the GSP area represented in Figure 21 68 through Figure 24. 69 Figures 2-21 through 2-24 include wells described previously as relatively shallow 70 groundwater wells, those with drilling depths of less than 500 feet. Figures 2-25 71 through 2-29 include wells described as deep groundwater wells, i.e., those with well 72 depths greater than 500 feet. 73

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74 75 Figure 2-21. Groundwater hydrograph for SWN: 48N04E22M001M

76 77 Figure 2-22. Groundwater hydrograph for SWN: 48N05E33H001M

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78 79 Figure 2-23. Groundwater hydrograph for SWN: 47N05E04M001M

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80 81 Figure 2-24. Groundwater hydrograph for SWN: 46N05E21J001M 82 83 As shown on Figures 2-21 through 2-24 relatively shallow groundwater wells within the 84 GSP area show minimal changes (less than 1 foot) in groundwater elevations when 85 comparing spring 2015 to spring 2019 groundwater elevations. This is indicative of 86 these wells pumping from the alluvial (shallow) aquifer which is likely recharged 87 through local precipitation, deep percolation of irrigation flows, and canal seepage. 88 Hydrographs of shallow wells throughout the GSP area identify a similar (minimal) 89 change in groundwater elevations during this time period. 90 91 In order to identify potential changes in groundwater elevations within the volcanic 92 aquifer underlying the GSP area, hydrographs of deeper groundwater wells (drilled 93 deeper than 500 feet) are identified in Figures 2-25 through 2-29. 94 95

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96 97 Figure 2-25. Groundwater hydrograph for SWN: 48N04E30F002M (TID Well No. 1) 98

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99 100 Figure 2-26. Groundwater hydrograph for SWN: 48N04E13K001M (TID Well No. 5) 101

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102 103 Figure 2-27. Groundwater hydrograph for SWN: 48N05E14R001M (TID Well No. 7) 104

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105 106 Figure 2-28. Groundwater hydrograph for SWN: 47N04E07Q001M 107

108

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109 Figure 2-29. Groundwater hydrograph for SWN: 46N05E22D001M (TID Well No. 14) 110 111 The hydrographs for deeper groundwater wells show a greater change in the 112 groundwater elevations from spring 2015 to spring 2019 as compared to the 113 hydrographs for the shallow groundwater wells. This deeper volcanic aquifer appears 114 to be primarily recharged through precipitation and the groundwater movement of 115 flows from north to south within the Upper Klamath Basin. The change in spring 2015 116 to spring 2019 elevation at these groundwater wells ranges from approximately -2 feet 117 to approximately +4 feet. 118 119 It is important to note, that the deeper aquifer is likely recharged from precipitation; 120 and therefore, groundwater elevation trends may be more directly impacted through 121 the quantity of groundwater extracted and climatic conditions. 122 123 2.2.2.2 Current Groundwater Elevations 124 The following figures represent groundwater elevation data from deep groundwater 125 wells (deeper than 500 feet), as these wells indicate the potential effects from both dry 126 hydrologic conditions and groundwater pumping within the deeper volcanic aquifer. 127 Figure 2-30 identify groundwater elevations and contours within the GSP area for 128 spring 2015 and spring 2019, respectively, prior to the groundwater pumping during 129 the subsequent irrigation season (ft, AMSL).

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130 131 Figure 2-30. Spring 2015 groundwater surface elevations.

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132 133 Figure 2-31. Spring 2019 groundwater surface elevations. 134 135 Figure 2-30 identify groundwater elevations and contours within the GSP area for fall 136 2015 and fall 2019, respectively, after the groundwater pumping during the most recent 137 irrigation season (ft, AMSL).

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138 139 Figure 2-32. Fall 2015 groundwater surface elevations.

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140 141 Figure 2-33. Fall 2019 groundwater surface elevations. 142 143 As discussed in Section 2.2.1.4 and shown on Figure 2-16, groundwater in the Upper 144 Klamath Basin generally flows toward Upper Klamath Lake, the Klamath River 145 Canyon, and the Tule Lake Subbasin (Gannett et al. 2007). 146 147 2.2.2.3 Vertical Gradients

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148 Vertical gradients can be used to describe the vertical movement of groundwater. 149 Typically, vertical gradients are measured by comparing the elevations of groundwater 150 in a well with multiple completions at different depths (multi-completion well). There 151 are zero multi-completion wells located in the Tule Lake Subbasin. While the existing 152 monitoring network is considered appropriate to monitor for trends, additional 153 monitoring wells, including a multi-completion well(s) would help improve the 154 understanding of the characteristics of the groundwater basin. 155 {TO BE COMPLETED AT A LATER DATE} 156 157 2.2.2.4 Groundwater Storage

158 Output from the model developed for this GSP was used to estimate the historical 159 change in groundwater storage for the Subbasin. Additional detail on use of the model 160 for water budgeting purposes is further discussed in Section X. Figure 2-34 shows the 161 annual change in storage and cumulative change in storage along with an indication of 162 the water year type1. In addition, shown on the figure below is the annual estimated 163 groundwater use by users within the District service area (“Irrigation & M&I 164 Groundwater Pumping”) and users outside of the District service area (“Private 165 Groundwater Pumping”). 166

1 Water year types provide an indication of hydrology and are described in the technical memorandum provided in Appendix A. 76

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0 20

0 -10

-20 -20 feet) - -40

-30

feet per year feet -60 -

-40 W LD D W LD W -80 1,000 acre LD

-50 (1,000 acre storage Change in D VW VD VD D -100 LD D D LD -60 -120 VD VD

-70 -140 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Water Year

Irrigation & M&I Groundwater Pumping Private Groundwater Pumping Annual Change in Storage Cumulative Change in Storage 167 168 Figure 2-34 - Estimated groundwater pumping and change in storage 169 170 2.2.2.5 Seawater Intrusion

171 Due to its geographic location, seawater intrusion is not a concern for the Tule Lake 172 Subbasin. 173 174 2.2.2.6 Groundwater Quality

175 Limited groundwater quality monitoring data are available within Tule Lake Subbasin. 176 In most instances, many of the groundwater wells have not been monitored frequently, 177 with many wells being sampled only once during the period of record for a parameter. 178 179 DWR Bulletin 118 generally describes the water quality of the groundwater within the 180 Tule Lake Subbasin as ranging widely in response to the source and proximity to 181 sources of surface and subsurface impairment. Water quality for wells constructed in 77

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182 the unconfined volcanic rocks within and adjacent to the Tule Lake Subbasin is good 183 with a sodium-bicarbonate character and a total dissolved solids (TDS) ranging from 184 150 to 270 mg/L. A shift in water quality is observed with the unconfined volcanics that 185 are proximate to lake sediments. The character shifts to a sodium/calcium/magnesium- 186 bicarbonate/sulfate water that is much higher in total dissolved solids (600 to 800 mg/L), 187 which generally increases in proportion to the penetrated thickness of interfingering 188 lake deposits (DWR, 2004). 189 190 The State Water Resources Control Board’s (SWRCB) GAMA Program has created tools 191 to analyze groundwater throughout the State. Appendix B includes water quality 192 information obtained from GAMA. A summary of key constituents in all wells 193 monitored in the subbasin, identified that major ions, volatile organic compounds 194 (VOCs), track elements, and total dissolved solids (TDS) can be found in high 195 concentrations throughout the subbasin. However, radionuclides, pesticides, and 196 nutrients are typically only detected at low concentrations. 197 198 The SWRCB performed an analysis of domestic well water throughout the state. Data 199 were collected over two years (summer 2017 – summer 2019) for chemical constituents 200 that have an established maximum contaminant level (MCL) or secondary maximum 201 contaminant level (SMCL) along with several other constituents. The top six 202 constituents were represented in the analysis: nitrate, arsenic, hexavalent chromium, 203 uranium, 1,2,3 trichloropropane (1234 TCP), and perchlorate. The results of this study 204 show that only arsenic exceeded the MCL of 10 micrograms per liter. Hexavalent 205 chromium is identified as unknown for the area. It is assumed that this constituent was 206 not tested for in the subbasin. The remaining four constituents did not exceed the 207 established MCL or SMCL. 208 209 2.2.2.7 Land Subsidence Conditions

210 Land subsidence is the lowering of the ground surface through compaction of 211 compressible, fine-grained strata. Compaction can be fully reversible (elastic) or 212 permanent (inelastic). Elastic compaction and expansion generally occur in response to 213 seasonal groundwater level fluctuations. Inelastic compaction is more likely to occur

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214 when prolonged dewatering of clay units occur during periods when the aquifer is not 215 fully recharged and groundwater levels reach historic lows. 216 217 Historically land subsidence was monitored along transects by comparing periodic 218 spirit level surveys conducted by the USGS and the National Geodetic Survey (NGS). 219 In the mid-1980s, a transition was made from the spirit level surveys to global 220 positioning system (GPS) surveys. Like spirit level transects, GPS monitoring of 221 subsidence relies on periodic resurveying of a network of monuments. In 2001, DWR 222 defined a network of monuments and preformed a GPS survey of the ground surface 223 elevation. In 2011, DWR re-surveyed 6 of the 23 monuments along the east and 224 southeast portion of the Subbasin to identify any potential land subsidence. Results 225 from the 2011 survey indicate that there has been no noticeable subsidence on the east 226 side of the Subbasin. 227 228 As part of DWR’s SGMA technical assistance, a statewide Interferometric Synthetic 229 Aperture Radar (InSAR) dataset was acquired. InSAR is a satellite-based remote sensing 230 technique that measures vertical ground surface displacement. TRE ALTIMIRA has 231 processed the InSAR data, and DWR has made available vertical displacement raster 232 data. Analysis of these images from 2015 through 2019 show that the Subbasin has not 233 experienced noticeable subsidence during recent years. TRE ALTIMIRA data for 2015 to 234 2016 and 2018 to 2019 are shown in Figures 2-35 and 2-36, respectively. 235

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236 237 Figure 2-35. Tule Lake Subbasin 2015-2016 Land Surface Displacement 238

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239 240 Figure 2-36. Tule Lake Subbasin 2018-2019 Land Surface Displacement 241 242 2.2.2.8 Identification of Interconnected Surface Water Systems

243 Interconnected surface water systems exist where there is a hydraulic connection 244 between water flowing in surface water streams and water in the adjacent aquifers. The 245 relative difference between the water surface elevation in the stream and aquifer 246 determines the direction of flow. Flow from the aquifer to the stream creates a “gaining

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247 stream” and occurs in areas where near-stream groundwater elevations are higher than 248 stream water surfaces. Areas where adjacent groundwater elevations are lower than 249 stream water surfaces indicate flow from the stream to the aquifer or a “losing stream”. 250 Figure 2-37 is a conceptual illustration of these two conditions. The direction of the flow 251 between a stream and aquifer can vary spatially along the length of the stream where 252 there can be gaining reaches and losing reaches. The direction can also vary through 253 time with a stream gaining during some months or years and losing at other times.

254 255 Figure 2-37. Gaining and Losing Streams (reproduced from USGS Circular 1376) 256 257 Interaction between groundwater and surface water in the Subbasin was analyzed 258 through the use of the model. Direct measurement of the gain or loss from surface 259 water to groundwater in the area is not feasible; however, the model provides sufficient 260 information to characterize interconnected surface water systems. The model was used 261 to develop estimates of timing and volume of gains and losses. Within the Subbasin, 262 natural surface water systems include the small reach of the Lost River which extends 263 into the Tulelake area and the “sumps”. 264 265 The Tule Lake National Wildlife Refuge (TLNWR) is located within the Subbasin and 266 primarily consists of four “sumps,” two of which act as regulating reservoir within TID

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267 (Sumps 1A and 1B). The other two sumps (Sumps 2 and 3) have been reclaimed and are 268 farmed as lease and co-op lands. The operational spills and tailwater resulting from 269 irrigation within TID are conveyed through TID’s extensive drainage system, which 270 utilizes gravity and pumped discharge into portions of the canal system or into the Tule 271 Lake Sumps. Water regulated and stored within the Tule Lake Sumps may be diverted 272 or rediverted for irrigation within TID or discharged by TID’s D‐Pumping Plant to the 273 P‐Canal, which serves the Lower Klamath National Wildlife Refuge (LKNWR) and the 274 water users on the P‐Canal system of the Project. 275 276 The sumps are operated by the District, and the surface water level must be maintained 277 at specified elevations throughout the year. Based on the Biological Opinion to protect 278 the endangered sucker fish, the sumps must be maintained at an elevation of at least 279 4,034.60 feet during April 1 through September 30; and, based on the Rules and 280 Regulations relative to flood control, the elevation is maintained at 4,034.00 feet the 281 remainder of the year. 282 283 2.2.2.9 Identification of Groundwater-Dependent Ecosystems

284 Groundwater Dependent Ecosystems (GDE) are defined in the SGMA Regulations as 285 “ecological communities or species that depend on groundwater emerging from 286 aquifers or on groundwater occurring near the ground surface” (23 CCR § 351(m)). 287 Identification of GDEs under SGMA is important because SGMA requires that all 288 beneficial uses and users be considered in the development of GSPs. 289 290 The Natural Communities Commonly Associated with Groundwater (NCCAG) 291 database was used to identify plants commonly associated with groundwater use. The 292 NCCAG was developed by a working group comprised of DWR, the California 293 Department of Fish and Wildlife (CDFW), and The Nature Conservancy (TNC), which 294 reviewed publicly available datasets of mapped seeps, springs, vegetation and 295 wetlands, and conducted a screening process to exclude types less likely to be 296 associated with groundwater and retain types commonly associated with groundwater. 297 Two habitat classes are included in the NCCAG dataset: 1) wetland features commonly 298 associated with the surface expression of groundwater under natural, unmodified 299 conditions; and 2) vegetation types commonly associated with the sub-surface presence

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300 of groundwater (phreatophytes). Figure 2-38 shows the wetland features and 301 vegetation areas identified in the NCCAG database.

302 303 Figure 2-38. Natural Communities Commonly Associated with Groundwater 304 305 However, identification as a NCCAG is not the same as being a GDE. An analysis was 306 performed to evaluate each NCCAG against criteria to determine if it is a GDE. The 307 criteria listed below identify characteristics which would make a NCCAG not a GDE. 308 309 1. Areas with a depth to groundwater greater than 30 feet – Oak trees are 310 considered the deepest-rooted plan in California with typical root zone depth of

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311 25 feet. TNC has developed guidance documents to help GSAs identify GDEs. 312 These guidance documents suggest that depth to groundwater greater than 30 313 feet would not support a GDE. NCCAGs in areas with depth to groundwater 314 greater than 30 feet are assumed to not access groundwater and are represented 315 as “Depth to Water” in Figure 2-39. 316 2. Areas adjacent to agricultural surface water – The majority of the Subbasin is 317 agricultural land and intersected by a system of irrigation canals, ditches, and 318 drains. The irrigation system brings in surface water which is available to the 319 NCCAGs. NCCAGs adjacent to irrigation conveyance facilities are assumed to 320 access the available surface water and are represented as “Stream/ Ditch 321 Adjacent” in Figure 2-39. 322 3. Areas adjacent to irrigated fields – Similar to areas adjacent to irrigation water 323 conveyance facilities, areas near irrigated fields benefit from the irrigation water 324 used to support crops. Irrigated fields are consuming the water that is applied 325 and, therefore, less water is available to adjacent ecosystems as compared to the 326 conveyance facilities. NCCAGs adjacent to irrigated fields are assumed to access 327 the available surface water and are represented as “Agriculture Adjacent” in 328 Figure 2-39. 329 4. Areas adjacent to the Sumps – As described in Section 2.2.2.8, water levels are 330 maintained in the sumps year-round. The sumps provide water for adjacent 331 ecosystems. NCCAGs adjacent to the sumps are assumed to access the available 332 surface water and are represented as “Sump Adjacent” in Figure 2-39. 333 334 The majority of the wetlands and vegetation shown are located along the perimeter of 335 the sumps or are adjacent to other surface water features. Areas remaining after the four 336 criteria above were applied are likely GDEs and were inspected in the field. 337 Photographs of these areas are included in Appendix X. 338 339 [insert GDE figure] 340

1 5 Monitoring Network 2 5.1 Description of the Monitoring Network (Reg. § 354.34) 3 This section discusses the monitoring networks identified to demonstrate short-term, seasonal, and 4 long-term trends in groundwater and related surface water conditions. In addition, these networks 5 assist with the evaluation of changing conditions that occur through implementation of the Plan. A 6 groundwater level monitoring network has been identified to avoid the undesirable result of chronic 7 lowering of groundwater levels. Monitoring of groundwater levels will support the understanding of 8 groundwater storage and be used as a proxy for the change-in-storage and land subsidence undesirable 9 results. A groundwater quality monitoring network has been identified to avoid the undesirable result of 10 degraded water quality. As discussed in Section 2.2.2.5 Seawater Intrusion, due to its geographic 11 location, seawater intrusion is not a concern for the Tulelake Subbasin. Therefore, a monitoring network 12 for seawater intrusion has not been identified. As discussed in Section 2.2.2.9 Identification of 13 Interconnected Surface Water Systems, the Lost River and Tule Lake Sumps are natural surface water 14 systems within the Tulelake Subbasin. These sumps are operated by the District and are highly regulated 15 based on the Biological Opinion. Therefore, a monitoring network for interconnected surface water 16 systems has not been identified.

17 5.2 Monitoring Networks Objective 18 The objective of the monitoring networks is to identify a sufficient number of wells that provides data to 19 demonstrate measured progress toward achievement of the Subbasins sustainability goal. In addition, 20 the monitoring networks are intended to support subbasin management actions and future updates to 21 this Plan. 22 The data from the wells within the monitoring network will continue to build on existing data to track 23 short-term, seasonal, and long-term trends in groundwater and related surface conditions. The 24 monitoring network, through evaluation of changes in groundwater levels, will support estimates of 25 annual changes in water budget components. 26 5.3 Monitoring Networks 27 The existing monitoring network described in Section 2.2.2.1 Historic Groundwater Elevations, was used 28 to develop the monitoring networks for this Plan. The monitoring networks for groundwater levels and 29 groundwater quality were selected to provide an adequate amount of spatial density and temporal 30 frequency to detect trends in groundwater conditions. The monitoring networks are described below. 31 5.3.1 Groundwater Level Monitoring Network 32 As discussed in Section 2.2.2.1 Historic Groundwater Elevations, groundwater elevations in the Tulelake 33 Subbasin are monitored monthly by DWR and other entities, including the District. Figure 2-19 identifies 34 the distribution of groundwater wells actively monitored for groundwater elevations within and near 35 the GSP area. 36 5.3.1.1 Representative Groundwater Level Monitoring Network 37 A subset of the groundwater level monitoring network was identified as the representative groundwater 38 level monitoring network based on their historical record of monitoring data and ability to represent 39 local, regional, and long-term trends in the Subbasin. The wells in the representative groundwater level 40 monitoring network were also selected based on their special distribution throughout the Subbasin and DRAFT

41 their construction/screening details. The representative groundwater level monitoring network is the 42 network that is used to monitor chronic lowering of groundwater levels, change in storage, and land 43 subsidence. Measurable objectives and minimum thresholds for monitoring sustainability have been 44 identified for each of the wells within this network. Table 5-1 identifies the wells within the 45 representative groundwater level monitoring network, including the construction details, current use, 46 monitoring agency, and monitoring frequency. Figure 5-1 shows the location of each of these wells 47 which are distributed throughout the Subbasin and located in proximity to groundwater production 48 wells. In addition, Appendix X includes the well completion reports for each of these wells. 49 Table 5-1: Representative Groundwater Level Monitoring Network

Perforations Well Location Well Approximate State Well (ft) Monitoring Depth Well Use Monitoring Number UTM UTM Agency (ft) Top Bottom Frequency East North 48N05E35F001M 634950 4646826 32 25 32 Domestic DWR Bimonthly 48N04E22M001M 623798 4649129 135 32 135 Domestic DWR Bimonthly 48N04E31M001M 618885 4645689 40 - - Domestic DWR Bimonthly 48N04E19C001M 619377 4649996 38 22 38 Domestic DWR Bimonthly 47N05E04M001M 631148 4644392 71 68 72 Industrial DWR Bimonthly 47N05E01N001M 636509 4643988 65 49 65 Domestic DWR Bimonthly 46N05E21J001M 632719 4630034 32 - - Domestic DWR Bimonthly 46N05E01P001M 636763 4634300 101 87 101 Domestic DWR Bimonthly 41S12E19Q001W 627992 4650692 65 - - Domestic DWR Bimonthly 48N04E30F002M 619583 4647681 740 260 700 Irrigation TID Monthly (TID Well 1) 48N04E13K001M 628217 4650610 1570 935 1557 Irrigation TID Monthly (TID Well 5) 48N05E26D001M 634823 4648412 1810 1250 1802 Irrigation TID Monthly (TID Well 8) 46N05E22D001M 633266 4630751 571 114 554 Irrigation TID Monthly (TID Well 14) TL-T1 Q3B 621062 4632384 500 - - Monitoring TID Monthly TL-T3 GP 627056 4633043 500 - - Monitoring TID Monthly

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50 51 Figure 5-1: Representative Groundwater Level Monitoring Network

52 5.3.1.2 Spatial Density of Groundwater Level Monitoring Network 53 The Tulelake Subbasin covers approximately 110,500 acres (approximately 172 square miles). As 54 described in Section 2.2.2.1 Historic Groundwater Elevations, there are approximately 70 groundwater 55 wells monitored in the Subbasin (see Figure 2-19). Therefore, the spatial density is approximately 40

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56 wells per 100 square miles, which is more robust than the spatial density guidelines recommended by 57 DWR in their best management practices (DWR, 2016){insert reference}. These recommendations from 58 DWR are summarized in Table 5-2. Of these wells, 15 have been included in the representative 59 groundwater level monitoring network. This spatial density of the representative is approximately eight 60 wells per 100 square miles. 61 Table 5-2: Monitoring Network Density Recommendations

Monitoring Well Reference Density (wells per 100 miles2) Heath (1976) 0.2-10

Sophocleous (1983) 6.3

Hopkins (1984)

Basins pumping more than 10,000 AFY per 100 miles2 4.0

Basins pumping between 1,000 and 10,000 AFY per 100 miles2 2.0

Basins pumping between 250 and 1,000 AFY per 100 miles2 1.0

Basins pumping between 100 and 250 AFY per 100 miles2 0.7 62 63 5.3.1.3 Groundwater Level Monitoring Protocols 64 In regard to District monitored groundwater wells, the District monitors on a monthly basis during the 65 year and on a weekly basis when the pumps are operating. The District enrolled in the CASGEM program 66 and prepared and submitted a groundwater monitoring plan to DWR (See Appendix X). Monitoring will 67 be performed following the protocols described in that plan. DWR typically measures monitoring wells 68 in the Subbasin on a bimonthly basis. 69 The monitoring frequencies, primarily monthly or bimonthly, allow for short-term and long-term 70 evaluation of trends and conditions. Monthly/bimonthly measurements are adequate for evaluation of 71 measurable objectives and minimum thresholds, while also showing fluctuations which may result from 72 storm events, droughts, seasonal variation, and groundwater pumping. 73 5.3.1.4 Subsidence Monitoring 74 Groundwater levels will be used as a proxy for monitoring of subsidence. Subsidence is the compaction 75 of soils in some aquifer systems as a result of groundwater being withdrawn. As mentioned in Section 76 2.2.2.7, there has been no noticeable subsidence within the Subbasin. Using groundwater levels as a 77 proxy for subsidence monitoring is adequate because subsidence will only occur if groundwater levels 78 are drawn below historical lows.

79 Although the Groundwater Level Monitoring Network will be used to monitor potential subsidence, the 80 GSAs will also review DWR’s active subsidence network. This network includes InSAR data for the 81 Subbasin. However, the data need to be processed and are not made available in real time. The data will 82 be reviewed as it becomes available to confirm the adequacy of the Groundwater Level Monitoring 83 Network. Monthly data for January 2015 through September 2019 were published March 2020. It is 84 unknown when additional data will be provided. If subsidence data relative to the Subbasin are made 85 available from other sources, this information will also be reviewed.

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86 5.3.1.5 Depletion of Interconnected Surface Water 87 As stated above, the only surface water within the Subbasin is a small portion of the Lost River which 88 terminates in the Tule Lake Sumps. This system is highly regulated as part of the US Bureau of 89 Reclamation’s Klamath Project. Due to the nature of the Lost River and Sumps, a separate monitoring 90 network for groundwater-surface water interaction has not been developed. However, DWR Monitoring 91 Well No. 48N04E22M001M is located adjacent to the Lost River and is included in the Groundwater 92 Level Monitoring Network.

93 5.3.1.6 Data Gaps 94 The existing groundwater level monitoring network is sufficient to meet the requirements of 95 implementing the GSP; however, the GSAs will continue to review the monitoring network and the 96 collected data to improve the understanding of the Subbasin and reduce uncertainty in collected data. 97 Specifically, additional wells can be added to the representative monitoring network to improve the 98 density and spatial distribution of wells throughout the Subbasin. In addition, there is a lack of dedicated 99 monitoring wells within the Subbasin. The GSAs will evaluate potential grant funding, including DWR’s 100 Technical Support Services, available to fund the construction of dedicated monitoring wells. One or 101 more multi-completion monitoring well would provide valuable data for the Subbasin. 102 Currently, there are no monitoring wells located in the middle of the Subbasin. However, there is also 103 limited groundwater pumping in this area (referred to as the “Lease Lands”). The GSAs will evaluate 104 potential grant funding, including DWR’s Technical Support Services, available to fund the construction 105 of a monitoring well in this area. Construction of a monitoring well will also be dependent on 106 cooperation from a wiling landowner. 107 5.3.2 Groundwater Quality Monitoring Network 108 As discussed in Section 2.2.2.6, there is limited groundwater quality monitoring within the Subbasin. 109 Because there are no known areas of degraded water quality or contaminant plumes which need to be 110 actively monitored, this monitoring network will rely on existing wells used for monitoring water quality 111 within the Subbasin which are public water supply wells. Other than the water quality study performed 112 by SWRCB, there is currently no groundwater quality monitoring performed by agencies within the 113 Subbasin. Figure 5-2 shows the Groundwater Quality Monitoring Network which includes the public 114 water supply wells.

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115 116 Figure 5-2: Groundwater Quality Monitoring Network

117 5.3.2.1 Representative Monitoring Network 118 The representative monitoring network includes all wells which are identified in the Degraded 119 Groundwater Quality Network. The representative network is used to evaluate nitrate and total 120 dissolved solids (TDS) thresholds and not other constituents. Table 5-3 summarizes the monitoring 121 frequency of the constituents for which sustainable management criteria have been established within 122 the Subbasin.

123 Table 5-3: Groundwater Quality Monitoring Network

Agency Number of Wells Constituent Monitoring Frequency City of Tulelake 2 Nitrate Every year TDS Every 3 years Newell County Water 2 Nitrate Every year District TDS Every 3 years 1 Nitrate Every year

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Klamath Basin National TDS Not monitored Wildlife Refuge 124

125 While only nitrate and TDS have established SMCs within the Subbasin, the GSAs will review data for 126 other constituents (e.g., chloride, copper, lead, sodium, hardness, coliform) monitored at the public 127 supply wells to track long-term trends.

128 5.3.2.2 Spatial Density 129 The groundwater quality monitoring network provides a spatial density of 2.9 wells per 100 square 130 miles.

131 5.3.2.3 Monitoring Protocols and Frequency 132 Water quality data collection protocols and frequency is established by the requirements of the Public 133 Water Suppliers within the Subbasin. The City of Tulelake GSA will provide its water quality monitoring 134 data as it becomes available. Monitoring data for the Newell County Water District and the Klamath 135 Basin National Wildlife Refuge will be obtained from the Drinking Water Watch website1.

136 5.3.2.4 Data Gaps 137 Groundwater quality monitoring gaps are the result of the need for denser and more frequent 138 monitoring, potential access issues, and areal coverage. The spatial density of wells in the groundwater 139 quality monitoring network is less than recommended by DWR in their best management practices. 140 Based on information in Table 6, an additional two wells should be added to supplement the monitoring 141 network.

142 Wells located in the northeast and southwest areas of the Subbasin will be evaluated for potential 143 inclusion in future monitoring network development. If possible, wells included in the groundwater level 144 monitoring network will be evaluated for benefit to the groundwater quality monitoring network.

145 5.4 Sustainability Indicators 146 [Placeholder for table identifying sustainability indicator associated with each monitoring well – to be 147 develop with Chapter 7]

1 https://sdwis.waterboards.ca.gov/PDWW/

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1 6 Water Budget Information (Reg. § 354.18) 2 The hydrologic cycle shown in Figure 6-1 below, describes how Earth’s water is moved, stored, and 3 exchanged between the atmosphere, land surface, and the subsurface.

5 6 Figure 6-1: The Hydrologic Cycle (Source DWR 2016)

7 A water budget takes into account the storage and movement of water between the four physical 8 systems of the hydrologic cycle. For the Tulelake Subbasin these four systems are the atmospheric 9 system, land surface system, surface water system, and the groundwater system. A water budget is a 10 tool to compile and compare inflows and outflows, the difference being the change in amount of water 11 stored. Figure 6-2 below, identifies the specific components of a water budget and their interactions. 12 Inflows are shown with blue arrows and outflows are shown with orange arrows. Flows between the 13 systems are shown with purple arrows.

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15 16 Figure 6-2: Water Budget Schematic (Source DWR 2016)

17 6.1 Water Budget Data Sources 18 Due to the complexity of some of the components, precise and accurate quantification of each 19 component of the water budget was not possible. Each component was estimated using readily 20 available data; however, nearly all involved some level of assumptions. In some cases, components were 21 roughly estimated to ensure that the budget is balanced, and both the budget and components are 22 deemed reasonable. Over time, with additional and improved data, a budget that more closely reflects 23 actual conditions will result in an improved tool for the Tulelake Subbasin. Appendix X {THIS WILL BE THE 24 MODELING REPORT} identifies the components of the water budget, data source(s), and assumptions. 25 The following sections describe water budgets for each of the systems shown in Figure 6-2: groundwater 26 system, land surface system, and surface water system (i.e., Tule Lake Sumps).

27 6.2 Historical Water Budget 28 The SGMA regulations require a 20-year historical period. Therefore, the Tulelake Subbasin 29 utilized a period of 1999 to 2018 for the historical water budget. Table 6-1 below summarizes the 30 historical groundwater budget. The SGMA regulations also require quantification of overdraft, 31 which is identified at the bottom of Table 6-1 as an average annual reduction in groundwater 32 storage of 5,000 acre-feet, which is small relative to the magnitude of the total inflows and 33 outflows. Therefore, it is not clear evidence of overdraft. Although the historical water budget 34 covers the period of 1999 through 2018, as defined in the SGMA regulations, GSPs are not 35 required to address undesirable results that occurred before, and have not been corrected by, 36 January 1, 2015. Therefore, this Plan is not required to address overdraft or other undesirable

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37 results that occurred prior to January 1, 2015. In addition, DWR’s 2020 Update to Bulletin 1181 38 identifies the Tulelake Subbasin as medium priority, meaning the subbasin is not in a state of 39 overdraft. 40 Table 6-1: Historical Groundwater Budget (1999-2018)

41 42

43 There are not active groundwater recharge projects in the Tulelake Subbasin; however, the Tule Lake 44 Sumps and the District’s conveyance facilities are unlined, which led to groundwater recharge as shown 45 in Table 6-1. In addition, with rising power costs, the District has minimized D-Plant pumping, which has 46 led to increased surface water recirculation and increased groundwater recharge.

47 Similar to the Groundwater Budget discussed above, a Land System Water Budget was prepared to 48 analyze and compare inflows and outflows for that system. The historical water budget for the land 49 system is included in Table 6-2 below.

1 https://water.ca.gov/Programs/Groundwater-Management/Bulletin-118#

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50 Table 6-2: Land System Water Budget (1999-2018)

51 52

53 The water budget for the Tule Lake Sumps is included in Table 6-3 below. The District estimates D-Plant 54 pumping, which is the only point of surface water outflow from the Subbasin. The D-Plant is operated, 55 as needed, to maintain water levels in the Tule Lake Sumps. Therefore, water budget for the Sumps was 56 prepared. Inflows to the Tule Lake Sumps include surface water from irrigation drains, gains from 57 groundwater, and precipitation. Outflows from the Tule Lake Sumps include irrigation diversions and D- 58 Plant pumping. As shown in Table 6-3 below, the Sump Imbalance is positive in 18 of the 19 years 59 analyzed. Therefore, the Tule Lake Sumps water budget is showing excess water in all but one year, 60 which indicates a conservative analysis.

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61 Table 6-3: Tule Lake Sumps Water Budget (2000-2018)

62 63 6.3 Current Water Budget 64 The current groundwater budget and land system budget is based on 2018 which is the most recent year 65 analyzed in the historical water budget and is included in Table 6-4 and Table 6-5 below. As shown, 66 inflows to the groundwater system exceeded outflows during 2018, which resulted in a positive change 67 in storage of approximately 17 TAF. The current water budget for the Tule Lake Sumps is included in 68 Table 6-3 above.

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69 Table 6-4: Current Groundwater Budget (2018)

71 72 73 Table 6-5: Current Land System Water Budget (2018)

74 75 76 6.4 Projected Water Budget 77 The SGMA Regulations require the preparation of a projected water budget, which must be based on at 78 least 50 years of historic climate data along with estimates of future land and water use. In addition, the 79 SGMA regulations require an analysis of future conditions with potential climate change incorporated. 80 As identified above, the historic period is 20 years long (1999-2018). Therefore, the climate data from 81 that period was repeated 2.5 times to achieve a 50-year period for projections. These data were used to

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82 develop the projected water budget baseline (i.e., without climate change). See Appendix X for further 83 discussion on this topic.

84 Table 6-6 below summarizes the projected groundwater budget baseline, which projects an average 85 annual change in storage of 0 acre-feet. This appears to be reasonable as there is no assumed change to 86 current crop patterns (which accounts for 55 percent of the land within the Subbasin). The Subbasin is 87 known to experience annual fluctuations depending on hydrology and surface water supply available 88 from the Klamath Project; however, groundwater levels in the Subbasin have remained relatively stable 89 over the last six years, with seasonal fluctuations.

90 91 Table 6-6: Projected Groundwater Budget Baseline

92 93 94 Figure 6-3 shows the complete water budget (1999 – 2071) without climate change. The gray line on the 95 figure shows the annual change in groundwater storage which fluctuates based on the balance of 96 inflows. The black line is the cumulative of the annual change in groundwater storage over the length of 97 the model period.

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98 99 Figure 6-3: Water Budget – future with no Climate Change

100 For the projected water budget with climate change, DWR provided alternatives for use by GSAs, which 101 included climate change factors. The US Bureau of Reclamation, in coordination with DWR and the 102 Oregon Water Resources Department, released the Klamath River Basin Study in 2019 (Study){ADD 103 reference}. The Study included evaluates water supply and demand including projected impacts of 104 climate change. The Tulelake Subbasin selected the 2070 central tendency alternative based on 105 knowledge of USBR modeling efforts of Klamath Project. Information from the Study provided estimated 106 impacts to mean Project Supply based on the 2070 central tendency which were incorporated into the 107 water budget model. In addition, 2070 central tendency climate change factors for temperature and 108 rainfall, developed and provided by DWR, were applied to the 50 years of projected climate data. See 109 Appendix X for additional information on this topic.

110 Table 6-7 below summarizes the projected groundwater budget baseline, which projects an average 111 annual change in storage of 0 acre-feet. As with the projection without climate change, this projection 112 seems reasonable as the 2070 central tendency scenario projects increased temperatures and increased 113 precipitation during the irrigation season. In addition, the Study projected little to no change in mean 114 Project Supply under this climate change scenario.

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115 Table 6-7: Projected Groundwater Budget with Climate Change Incorporated

116 117 118 Figure 6-4 shows the complete water budget (1998 – 2071) with climate change. The gray line on the 119 figure shows the annual change in groundwater storage which fluctuates based on the balance of 120 inflows. The black line is the cumulative of the annual change in groundwater storage over the length of 121 the model period.

122 123 124 125

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126 127 Figure 6-4: Water Budget - future with Climate Change

128 The SGMA Regulations require Plans to identify an estimate of the sustainable yield for the subbasin. 129 This requirement is interpreted as the average annual groundwater pumping that can occur, which does 130 not lead to overdraft of the groundwater resource. As shown in Table 6-7 and Figure 6-4, the projected 131 average annual long term groundwater pumping is approximately 48,000 acre-feet. The Tulelake 132 Subbasin has historically demonstrated that the Subbasin can accommodate that level of groundwater 133 pumping, which is further confirmed through the projected water budgets. Therefore, the estimated 134 sustainable yield for the Tulelake Subbasin is 48,000 acre-feet. The estimate of sustainable yield will be 135 re-evaluated in future updates to this GSP as additional information becomes available.

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