Working Draft Groundwater Work Group Recommendation: 1

Transcription

1 Working Draft Groundwater Work Group Recommendation: 1 I. Groundwater Work Group s Charge (Revised by the Center for Collaborative Policy to reflect Groundwater Work Group discussions to date) The Groundwater Work Group is a subgroup of the Owens Lake Master Project Advisory Committee, convened by the Los Angeles Department of Water and Power (LADWP). LADWP charged the AC with providing advice to LADWP on how to refine the draft description of LADWP s proposed Master Project for Owens Lake prior to the initiation of the procedures required by the California Environmental Quality Act (CEQA). The draft Master Project description focuses on dust control on the dry Owens Lake bed, and conveys LADWP s desire to use groundwater as part of its dust control strategy. The Advisory Committee established the Groundwater Work Group to formulate for the Advisory Committee s consideration a proposed recommendation to LADWP on: a) whether it may be feasible to use groundwater as part of the dust control work central to LADWP s proposed Master Project for Owens Lake without significant 2 impacts to Owens Valley s ecological 3, cultural, or socio-economic systems as defined by the Resource Protection Protocols (currently under development); b) if so, under what conditions; and c) if not, why not. The Groundwater Work Group is co-chaired by Dr. Saeed Jorat (LADWP) and Dr. Bob Harrington (Inyo County Water Department). II. Approach Groundwater Work Group members have approached their charge through listening to presentations, reviewing documents, and discussing the meaning and implications of this information with LADWP staff, consultants, and one another. They met for the first time in October 2013, and have met approximately monthly since then. Work Group members reviewed the proposed Master Project design and the proposed Owens Lake Groundwater Development Project to familiarize themselves with the manner in which the initial project definition incorporates groundwater use for dust control, and based on this review, consider whether the composition of Groundwater Work Group and/or Advisory Committee should be 1 A working draft document is one that should be seen as a work in progress. Nothing in it should be construed as agreed-upon until it is finalized. 2 Significant is used throughout to mean no negative impacts as defined in the Resource Protection Protocols. If this definition is found to conflict with other definitions of significant, the definition contained in the Resource Protection Protocols should prevail. 3 Ecological is defined to include groundwater. 1

2 refined to ensure all major stakeholders are invited to participate in subsequent steps in some manner. No needed adjustments to the Work Group composition were identified. Since then, Work Group members have been reviewing pertinent documents and receiving presentations from technical consultants. Four of the most central sources of information to date have been: 1. LADWP s draft document entitled, Approach to Future Groundwater Development at Owens Lake, (January 15, 2013); 2. A presentation by Work Group Co-Chair Dr. Saeed Jorat (LADWP) on LADWP s proposed approach to groundwater development at Owens Lake, including associated PowerPoint slides; 3. A presentation October 29, 2013, by LADWP consultant Victor Harris with the firm of MWH on a model of Owens Lake groundwater dynamics and the hydrologic system s anticipated response to possible groundwater pumping (developed for LADWP by MWH); and 4. A detailed question-and-answer session between Work Group members and the LADWP team during the Work Group meeting of January 20, 2014, along with a detailed summary thereof. Groundwater Work Group members also have coordinated with the full Advisory Committee and with members of other work groups as needed in an effort to ensure that the recommendations of this Work Group integrate appropriately with those emerging from other work groups. Groundwater Work Group members have been working particularly closely with the Habitat Work Group, seeing it as: a) the Groundwater Work Group s responsibility to articulate its members understanding regarding what is known and unknown about the hydrologic system s expected response to groundwater pumping; and b) the Habitat Work Group s responsibility to articulate its members understanding about what is known and unknown regarding how ecological systems would respond to those changes in the area s hydrologic system. To carry out the cultural component of its charge, the Groundwater Work Group agreed with LADWP s technical consultant, ESA, that ESA s senior archaeologist would work with area tribes to develop proposed Cultural Resource Protection Criteria for consideration by the Advisory Committee as a whole (called Cultural Resource Protection Protocols henceforth, for consistency with similar work products being developed for other resources). The next section contains the Groundwater Work Group s initial recommendations. These recommendations are based on the Work Group s understanding of LADWP s proposed Master Project. Appendix A describes the Work Group s understanding of the proposed Master Project. 2

3 The Work Group reserves the right to revise its recommendations if any of those understandings are incorrect. The Groundwater Work Group s final recommendations are dependent on the content of Resource Protection Protocols, which are currently under development. (These Protocols are defined in the section below.) Thus, the Work Group will be unable to finalize its recommendation until the Resource Protection Protocols are finalized, and it is vital to Work Group members to have input into the content of the Protocols. The Work Group suggests that relevant portions of the recommendations that follow be incorporated into the Resource Protection Protocols; please see Appendix B for excerpted portions of the Work Group s recommendations that may be appropriate to use in that way. The Groundwater Work Group would like to reconvene to finalize its recommendation once the draft Resource Protection Protocols are ready for members review and comment. III. Groundwater Work Group s Initial Recommendations The Groundwater Work Group s initial recommendations to LADWP on: a) whether it may be feasible to use groundwater as part of the dust control work central to LADWP s proposed Master Project for Owens Lake without significant impacts to Owens Valley s ecological, cultural, or socio-economic systems; b) if so, under what conditions; and c) if not, why not, is embodied by the entirety of Section III below. They are referred to as initial because the group has identified the need for the development of groundwater-related Resource Protection Protocols (RPPs) and a Hydrologic Monitoring, Management, and Mitigation Plan (HMMMP) to guide adaptive management during potential project implementation in order for the group to get closure on whether they believe it is feasible to use groundwater as part of LADWP s proposed Master Project for Owens Lake without significant impacts. Thus, the present recommendation can be thought of as a recommendation about how to determine whether it is feasible. A. Key Concepts 1. Adoption of Groundwater Management Plan. The HMMMP should be included in the CEQA analysis as a mitigation measure for potential significant impacts due to groundwater pumping, as described in the RPPs. The adoption of the HMMMP as a mitigation measure will provide for future enforceability of Master Project groundwater management elements. The HMMMP should be subject to the approval of Advisory Committee members. 2. Phased Implementation. Phased implementation of the project, as proposed by LADWP, is a good approach. 3

4 3. Management Objective. The overall objective of groundwater management should be to avoid significant impacts to groundwater and groundwater-dependent resources as described in the RPPs. Mitigation should be used to address situations in which LADWP falls short of the goal of avoiding significant impacts to groundwater and groundwater-dependent resources, rather than as a primary resource protection strategy. 4. Definition of Significant Impact. Significant is defined throughout by impact limits as specified by the Resource Protection Protocols (RPPs) for each resource. (RPPs are defined in Item 6 below.) 5. Feasible Amount of Groundwater Use. The amount of groundwater that can be pumped is that amount that has: a. no significant impact on groundwater and groundwater-dependent resources; and b. is subject to the pre-agreed-upon HMMMP. The amount of groundwater use will be controlled by monitoring thresholds that protect groundwater dependent resources from significant impacts as defined in the RPPs (see #III.A.6. and III.G.4. below). 6. Resource Protection Protocols. The RPPs will identify potentially affected resources, define levels of significant impact for such resources, and propose quantitative thresholds that, if exceeded, would require LADWP to take management actions (which may include more intensive monitoring up to ceasing groundwater pumping) to avoid significant impacts. The Groundwater Work Group has identified the need to develop RPPs for groundwater and groundwater-dependent resources, which the Work Group considers to include air quality with respect to potential increases in dust emissions, land elevation with respect to potential subsidence on or off the defined lake bed, infrastructure such as non-ladwp wells and buildings to protect them from potential impacts resulting from groundwater pumping, including groundwater drawdown, and groundwater-dependent vegetation/habitat. The Groundwater Work Group anticipates that all RPPs will ultimately be documented in one place (e.g., building upon and updating the most recent draft Resource Protection Criteria table). All impacts will be listed regardless of their mitigatability. A separate document will outline and evaluate potential mitigation measures. The Resource Protection Protocols will include: a. The objective for each resource (e.g., preserve spring snail habitat); 4

5 b. The hydrologic condition that needs to be maintained for the resource (e.g., avoid decreasing west side springs flow by more than 10%); c. Monitoring thresholds (e.g., criteria or standards) that, if exceeded, would trigger the need for management action in order to maintain the necessary hydrologic condition (e.g., groundwater elevation in a monitoring well must not decline below a specified level); and d. Management actions that must be taken if specific, pre-agreed-upon monitoring thresholds are exceeded. The objective and hydrologic condition for each resource will essentially define what a significant impact is. The monitoring threshold should be set so that a significant impact is avoided; that is, the threshold is set so that hydrologic conditions exceed those necessary to meet the objective Monitoring and Adaptive Management Plan. The HMMMP should include a monitoring plan for the purposes of: (1) establishing baseline conditions; (2) implementing the resource protection methods described above; (3) updating and refining monitoring thresholds in the RPC for each resource to ensure protection of resource(s); and (4) improving the predictive capabilities of the groundwater model. Data collected on habitat and pumping impacts should be available on-line on a reasonable schedule. Environmental / habitat data should be available annually. Hydrological data should be available quarterly. The data should include whatever is needed in order to evaluate (and report) on conditions relative to the RPPs (including what can be derived from monitoring wells in all potential impact areas, reports of unexpected subsidence, vegetation changes or reduction outside Owens Lake perimeter, spring levels and flows, etc.). The adaptive management function must be ongoing due to impacts, climate, regulation, etc., that can influence pumping limits and opportunities. 8. Potential Impacts. If significant impacts as described in the RPPs occur and appear to be due to Master Project-related groundwater pumping, LADWP should: a) have the burden of proof to show that the impacts are not due to the Master Project; and b) mitigate impacts due to the Master Project to the fullest extent feasible. 4 Once Resource Protection Protocols are done, we need Pete s input on behalf of HWG regarding a trigger that includes observable impact to resource or resources habitat. 5

6 B. Inter-Dependent Relationship of Groundwater Work Group Recommendation and Resource Protection Protocols It may be possible to use groundwater as part of the dust control work central to LADWP s proposed Master Project for Owens Lake without significant impacts to Owens Valley s ecological, cultural, or socio-economic systems if sufficient protections are put in place and followed faithfully. However, we cannot finalize our recommendation on this question until the protections to be documented as Resource Protection Protocols -- are written. Below and in Appendix B, we identify groundwater-related text for inclusion in the Resource Protection Protocols. C. Benefit to Owens Valley To the extent that ground water development reduces LADWP s need to divert water from the aqueduct, a measurable fraction of that water will be retained for use in Owens Valley. D. Geographic Boundaries The boundaries of the proposed Master Project have consistently been defined as within the 3600 foot contour of the dry Owens Lake. Production wells will only be placed below the 3600 contour, south of and downstream from the pumpback station. The study area should extend beyond the 3600 area for CEQA analysis and monitoring.. E. Applicable Conditions Necessary to Protect Owens Valley s Ecological, Cultural, or Socio-economic Systems From Significant Impact Associated With Master Project-Related Groundwater Pumping 1. The amount of groundwater pumping will be controlled by monitoring triggers that protect groundwater dependent resources from significant impacts. Significant impacts are defined by Resource Protection Protocols that cover: a) habitat; b) cultural resources; c) non-ladwp wells; d) subsidence; and e) air quality. a. Criteria for habitat are being developed by the Habitat Work Group. b. Criteria for protecting cultural resources are being developed by ESA and area tribes collaboratively; Advisory Committee/Groundwater Work Group members are developing input to that process in the form of a list of 6

7 groundwater-sensitive plants on the lake bed and its periphery. The Groundwater Work Group recommends that groundwater pumping should be subject to the protection criteria currently being developed for cultural resources by ESA and area tribes. In addition, the Groundwater Work Group assumes that all applicable legal protections for cultural resources stand. c. Criteria for non-ladwp wells, subsidence, and air quality are being developed by the Groundwater Work Group in the context of this document, as follows: 2. Resource Protection Protocols for Non-LADWP Wells: a. Impact to non-ladwp wells may take the form of either lowering the water level or degradation of water quality in a well. If impacts occur despite the RPPs, appropriate mitigation will need to be defined situationally, given the variation in well characteristics. However, LADWP should confer with all identifiable and interested non-ladwp well-owners on the lake bed 5 or surrounding areas to get their input on how to define those two terms and the most acceptable way to proceed in establishing a baseline. These consultations are important enough that LADWP should be prepared to slow down the overall Master Project timeline to provide the time to do a thoughtful job on this. 6 Below is an initial suggestion about how the baseline might be established, recognizing that for LADWP to have a functioning baseline, they will need input from other well-owners and the below recommendations assume that such a baseline is able to be established; however, the Groundwater Work Group recommends that the approach below be refined to reflect well-owner input as described in this paragraph. b. To minimize potential conflict over defining impacts and whether an impact can be attributed to Master Project-related groundwater pumping: i. LADWP should accept the burden of proof to show that any particular impact is not due to Master Project-related groundwater pumping. 5 Lake bed is defined to mean the area within the 3600 foot contour around Owens Lake. 6 Would that be part HMMMP? 7

8 ii. To make 2.b.i. viable, LADWP will need to make a diligent and thorough effort to establish a baseline of static water level, well construction, and water quality in all non-ladwp wells that could potentially be affected by groundwater pumping for this project. iii. iv. Once an estimate of the number of non-ladwp wells are determined (e.g., through a search of the well drilling report of the Inyo County Environmental Health Department), the most appropriate method of baseline data collection can be determined. As a default approach, the Groundwater Work Group suggests that LADWP is likely to be most successful in accomplishing this task through a public outreach effort, including a mailer to known private well owners and news media announcements. The Groundwater Work Group recommends that the well-owner consultations referenced above be funded by LADWP, but carried out by an objective 3 rd party contractor through a contracting mechanism that protects their independence. For example, LADWP could provide funds to the County, and the County could hire the contractor and manage the contract (subject to County Board approval). Well-owners participation in baseline data collection should be voluntary and at no expense to the well-owner. Further, well-owners who opt not to participate should not be penalized. The choice of whether or not to participate in setting the baseline should have no effect on whether a well-owner is eligible for mitigation for potential future impacts due to the Master Project. Nothing in this recommendation is intended to modify current legal protections available to well-owners. 8

9 3. Resource Protection Protocols for Subsidence: 7 a. Prior to the start of Phase II of the proposed Master Project, LADWP should survey a network of benchmarks to establish a topographic baseline against which to measure potential subsidence associated with Master Project groundwater pumping. 8 LADWP should take measurements annually to monitor for potential subsidence, with reference to the baseline established under E.2.b. above. i. During Phase I, evaluate what level of subsidence attributed to this project would be significant for Owens Valley inside or outside the lake bed (as determined by LADWP engineers analyzing the amount of slope in the shallow flooding areas that would require them to be reconstructed, and that would cause the brine pool to migrate). ii. iii. iv. If subsidence exceeds that level on the lake bed or surrounding areas, groundwater pumping should be evaluated to determine the cause. That portion of the pumping contributing to the problem would remain stopped unless or until some other form of mitigation were agreed to by those affected. If subsidence impacts are observed on the lake bed or surrounding areas, even though subsidence has not exceeded the threshold level of subsidence, the cause of subsidence should be evaluated. If groundwater pumping is determined to be the cause, mitigation should be implemented to prevent subsidence reaching a pre-agreed-upon threshold. (Exception: If impacts only affect LADWP infrastructure, LADWP could choose how to mitigate the impact.) If a property owner believes that a subsidence impact has occurred and is attributable to the Master Project groundwater pumping, the burden of proof should be on LADWP to demonstrate that either of those things is not true. 7 Will the HMMMP address this? 8 Note that subsidence impacts may include water quality. 9

10 4. Resource Protection Protocols for Air Quality: a. LADWP should take every precaution to avoid increasing dust emissions as a result of groundwater pumping. LADWP should take full responsibility for fully mitigating any increased dust emissions resulting from the Master Project groundwater pumping in spite of such precautions, whether the emissions are observed in the air column over the lake bed or in the surrounding area. i. Before the end of Phase I, LADWP will develop a map of the areas that could be susceptible to increased dust emissions as a result of groundwater pumping at Owens Lake. LADWP will include areas beyond the defined lake bed if they would be susceptible in this way. ii. If increased emissions resulting from the Master Project groundwater pumping occur, LADWP should immediately stop pumping. 9 That portion of the pumping contributing to increased dust emissions would not resume unless or until some other form of mitigation were agreed to by the parties affected. b. If LADWP does not believe that increased emissions have occurred due to the Master Project pumping, LADWP should have the burden of proof to show that. Having a pre-agreed-upon map of susceptible areas should help to make this viable. c. Nothing in this recommendation is intended to modify current air quality protections available under the law. 5. Data Access and Reporting: The HMMMP should provide for access to all data collected under the monitoring plan. New data should be made available on-line at least bi-annually in a format that allows non-ladwp parties to analyze the data. Advisory Group members should be able to request and obtain any specific data 10 related to the project at no cost and in a timely manner. 9 What entity determines if increased dust emission is due to pumping at Owens Lake? 10 Can we be more specific i.e., pumping rates and groundwater levels? 10

11 F. Linkage Between Groundwater and Habitat Suitability Models 1. Modeling is a tool, and represents only what the modeler thinks will happen. LADWP should think in terms of adaptive management with respect to ascertaining that the groundwater flow model is actually accurate enough to guide decision-making in this situation. Since environmental factors vary so widely, it will be important to establish metrics associated with the habitat and cultural Resource Protection Protocols that are: a) actually detectable; and b) tie closely to groundwater pumping. The Resource Protection Protocols themselves may need to evolve over time, also in a phased manner, coordinated with the three phases of LADWP s proposed groundwater development program. 2. (More to be added once HWG develop proposed habitat protection criteria) G. Monitoring and Adaptive Management Strategy / Phased Approach 1. Given the importance of ensuring that groundwater pumping is sensitive to the RPPs (once formulated), and the number of unknowns and model uncertainties, a phased approach is the only way to proceed in exploring the possibility of using groundwater in this situation. 2. The level of groundwater pumping must be limited by the RPPs (once developed and agreed to by the Advisory Committee). 3. For the phased approach to be an effective form of adaptive management, managers must have the authority and flexibility to take prompt management action (including ceasing groundwater pumping) if the RPPs (under development) are triggered. 4. The RPPs and/or HMMMP should contain a series of monitoring thresholds, with the most conservative thresholds (e.g., the first that would be triggered) set conservatively so that, if triggered, there is time to handle the operational changes (e.g., shifting to an alternative water source) necessary to avoid pump shutoff if possible. Subsequent monitoring thresholds should be in place to provide alerts if the situation is worsening. Among the monitoring thresholds specified in the RPPs should be one that indicates the situation is so serious that LADWP should immediately stop groundwater pumping until the reason for that threshold exceedence can be determined. Pumping should only be resumed if impacts can be avoided. LADWP must establish and maintain the ability to quickly switch water sources from groundwater beneath the lake bed to alternative sources in order to 11

12 be prepared to smoothly handle operational needs in situations in which groundwater pumping must stop. In recognition of the fact that LADWP is legally responsible for mitigationing dust in the area, groundwater pumping should not be initiated unless such an alternative water source is available so that if groundwater protection thresholds are exceeded, LADWP can immediately stop pumping without being in violation of the Clean Air Act. 5. LADWP must take prompt management action in response to whichever aspect of the RPPs is triggered first. This is intended to convey the Groundwater Work Group s view that all resources vulnerable to significant impacts (as described in the RPPs) from groundwater pumping are equally important. 6. The design for a potential adaptive management program for the proposed Master Project should build on lessons learned from adaptive management efforts elsewhere (e.g., in the context of the Lower Owens River Project). H. Stakeholder Input During RPP and HMMMP Development The Groundwater Work Group recommends that LADWP continue to convene the Work Group on an as-needed basis during development of the RPPs and HMMMP to review drafts and provide input. The Groundwater Work Group would like to review the work plan for development of the RPP and HMMMP, ideally by September I. Stakeholder Role During Project Implementation If the proposed Master Project proceeds, LADWP should work with a diverse stakeholder group like the Groundwater Work Group to monitor implementation and help ensure that the phased / adaptive management approach works effectively. The Work Group anticipates that meetings between one and four times per year would be appropriate during implementation. 12

13 Appendix A Groundwater Work Group s Understanding of LADWP s Proposed Master Project The Groundwater Work Group s recommendation is based on the following understandings: A. Groundwater system. 1. Aquifers beneath the playa are confined by thick clay layers and are under artesian pressure. Confined aquifers beneath the playa are largely disconnected from surface water features such as the brine pool and areas where dust is controlled using shallow flooding. 2. Faults influence groundwater flow. The permeability of faults determines how much and how quickly pumping effects will propagate across faults to potentially affected resources. LADWP seeks further testing during Phase I to explore the extent and manner in which these faults act as barriers to groundwater flow. 3. The conceptual model described by MWH indicated that groundwater pumping from deep aquifers is unlikely to have impacts on shallow groundwater levels beneath the lake bed, 11 but will affect groundwater levels beyond the perimeter of the playa where aquifers that are confined beneath the playa transition to unconfined aquifers beneath the alluvial fans adjacent to the playa. Groundwater levels and groundwater gradients beneath the alluvial fans likely affect many of the springs and seeps at the playa margin. Springs controlled by faults (e.g., spring mounds) and flowing wells may be directly affected by pumping from deep aquifers. 4. Measuring groundwater discharge in the spring line around the perimeter of the playa is complicated because in many cases, because the discharge is through diffuse seeps rather than from discrete spring vents. Where discrete spring vents are present, often the first practical measurement point is some distance downstream of the spring. The resulting measurement may be seasonally affected by evapotranspiration occurring between the spring itself and the measurement point. Measurements from shallow monitoring wells up on the alluvial fan are expected to be less affected by evapotranspiration and provide early warning for pumping effects on springs. LADWP has proposed to use such monitoring wells in lieu of spring flow as triggers to manage pumping before significant impacts occur. LADWP believes this measurement approach looks 11 Lake bed is defined to mean the area within the 3600 foot contour around Owens Lake. 13

14 feasible based on the conceptual model, pending refinement of the model based on testing well data obtained in Phase I. Appropriate trigger levels in such monitoring wells are as yet unknown, pending (1) collection of baseline groundwater level data in monitoring wells, and (2) establishment of a Resource Protection Protocolsfor potentially affected springs. Unknown is the correlation with drawdown at the alluvial fans and the vegetation/habitat on and around the lake bed. B. LADWP s Proposed Approach to Exploring the Feasibility of Future Groundwater Development at Owens Lake 1. LADWP proposes to explore the feasibility of using groundwater as part of its dust control strategy at Owens Lake using a phased, adaptive management approach. This means that they would adjust plans for the next phase according to what is learned during the preceding phase. Phases I and II are each anticipated to last three years (for a total of six years), followed by Phase III.Production pumping is expected to begin in Phase II and to increase in Phase III. In general terms, Phase I began in April 2013 and focuses on: a) collecting information needed to fine-tune the model of groundwater dynamics and the hydrologic system s response to groundwater pumping (developed for LADWP by technical consultant MWH); b) environmental studies; and c) permitting. LADWP considers this phase pre-project. Phase I would involve pumping for test purposes to assess the effect of faults on groundwater flow. All discharged water during testing will be used on the project, providing that necessary State Lands Commission approvals are received. (Phase I pumping tests located on State-owned lands require the submittal of a lease application and consideration by the Commission. In addition, the use of any discharge water for use on the project would also require the submittal of a lease application and consideration by the Commission.) Phase II will initiate production pumping and may include additional pumping locations. Phase III would entail transition to full project implementation of Master Project groundwater pumping and management and may also involve additional pumping locations LADWP anticipates that the Resource Protection Protocols currently under development (see Section III.A.6.) will identify potentially affected resources, 12 Regarding timing of the transition to low/no water BACM, once such BACM are approved, they will be used. If water is available, it may be used; it would replace LAA water, not augment it. 14

15 define levels of significant impact for such resources, and propose quantitative thresholds that, if exceeded, would require LADWP to take management actions (which may include more intensive monitoring up to ceasing groundwater pumping) to avoid significant impacts. Resource Protection Protocols are currently being developed for habitat by the Habitat Work Group and for cultural resources by ESA in consultation with area tribes (to be discussed at Advisory Committee level). The Groundwater Work Group has also identified the need to develop a Resource Protection Protocols for infrastructure such as non-ladwp wells and buildings to protect them from impacts resulting from groundwater pumping, including groundwater drawdown, impacts to vegetation/habitat or subsidence on or off the defined lake bed. The Groundwater Work Group anticipates that all Resource Protection Protocols will ultimately be documented in one place (e.g., building upon and updating the most recent draft Resource Protection Criteria table). All impacts will be listed regardless of their mitigatability. A separate document will outline and evaluate potential mitigation measures. 3. LADWP has indicated that the levels of groundwater pumping that might occur will range from zero upwards, depending on whether and at what point the Resource Protection Protocols are triggered by groundwater pumping. The phases will allow LADWP to implement the Resource Protection Protocols by monitoring the hydrology, impacts on resources, and habitat variables response to low levels of pumping, and then re-assess next steps. 4. No water extracted through this OLGDP (during any project phase) will be sourced outside the area bounded by Highway 395, Highway 190, and Highway 136. Such water will be used only for dust control measures and related maintenance on the Owens Lake control areas. 5. LADWP wants to maximize groundwater use while avoiding the potential for impacts from groundwater pumping. To accomplish this, MWH has recommended pumping from a blend of shallow, deep, and flowing wells (as long as the result was consistent with the resource protection Protocols). LADWP plans to identify the specific proposed well configuration after test pumping is completed and evaluated, and the groundwater model is updated, with the intent of identifying locations from which to pump that would prevent significant impact to resources. The Groundwater Work Group underscores the importance of assessing and avoiding groundwater pumping impacts to resources outside of the project footprint, and committing to fully mitigating them if they should occur. 15

16 6. LADWP is developing baseline information on groundwater levels using historic data as well as ongoing monitoring in the 14 shallow monitoring wells installed in 2013, as well as the 28 deep monitoring wells installed in The historic data includes: a) fifty years of monitoring data at Cottonwood Spring; and b) Great Basin s twenty years of data on spring flow and groundwater levels, ongoing since 1992 (with increasing intensity over the years). LADWP anticipates that the baseline will be defined by the end of Phase I. 7. LADWP proposes to install two testing wells during Phase I, which would be used to conduct test pumping to determine the hydraulic characteristics of faults. Both of these will be south of the pumpback station. More specifically, these wells are intended to test the extent to which faults the Owens Valley Fault and the Owens River Fault would serve as barriers to groundwater flow. 13 The baseline needs to be established before Phase II pumping would begin. 8. LADWP does not yet know where and how many wells would be installed during Phases II and III; that would be determined based on monitoring results. However, LADWP will not put production wells outside the area bounded by Highway 395, Highway 190, and Highway LADWP is committed to maintaining habitat values, and sees the Habitat Suitability Model and the Resource Protection Protocols (under development) as primary tools for doing that. 10. The purpose of the groundwater model is to design a groundwater pumping program that does not result in significant impacts as defined by the Resource Protection Protocols. The model will be updated iteratively as additional data become available. 11. LADWP anticipates preparing a programmatic Environmental Impact Report (EIR), relying on a combination of the Resource Protection Protocols and adaptive management rather than on detailed project specifications. Inyo County has indicated that the groundwater elements of the Master Project should be set forth in plan that is adopted through the CEQA process and thus enforceable as a CEQA mitigation measure. Specific project components (e.g., construction of wells) may require additional CEQA analysis. 13 This testing is not expected to significantly affect baseline values. 16

17 C. Non-LADWP Wells 1. MWH s final report to LADWP on the Owens Lake Groundwater Evaluation Project includes a table of predicted drawdown at a number of non-ladwp wells. It shows some drawdown, but since the depth of these non-ladwp wells is unknown, it is not known if these drawdowns are significant impacts. Water quality effects on non-ladwp wells are largely unknown, and should be monitored. LADWP is committed to mitigating significant impacts to non-ladwp wells caused by the project. D. Subsidence 1. Subsidence is usually expected where thick clay layers are depressurized by pumping. Such clay layers are found under the lakebed area. LADWP does not anticipate subsidence occurring off the lakebed due to the expected drawdown and lack of thick clay layers in the alluvial material outside the lake bed. (However, LADWP is responsible for any inadvertent subsidence impacts due to the OLGDP Project.) The principal of subsidence are negative effects due to differential subsidence on LADWP s dust control measure infrastructures and on the Rio Tinto trona mining lease. The dust control measures may be affected by changes in topographic slope changing the distribution of water in shallow flooding areas, or by damage to water conveyance infrastructure. Rio Tinto s operation may be impacted [e.g. damage to roads and equipment, mining panel seal structure by slumping or fracture, and changing the location of the low center of the lake bottom (potentially moving the brine pool and the mineral deposit area)]. 2. By the end of Phase I, LADWP plans to determine what level of subsidence would be acceptable. LADWP s current working answer to that is that they would not want more than one half foot of subsidence, which they understand to be the amount that is generally accepted in the CEQA context. 14 LADWP is open to modifying that based on Advisory Committee / Groundwater Work Group input and Phase I monitoring results. After updating of the conceptual and computer models of Owens Lake, LADWP plans to use the groundwater model to develop a 14 The identification of this threshold level of subsidence should be determined by LADWP engineers analyzing the amount of slope in the shallow flooding areas that would require them to be reconstructed, and that would cause the brine pool to migrate. 17

18 map showing the aerial extent of the area that could be potentially subject to land subsidence by taking into account the updated hydro-geologic model of Owens Lake and the and the maximum amount of the groundwater pumping. This map will then be used to develop a monitoring plan for subsidence including the locations and frequency of monitoring. 18

19 Appendix B Excerpts from Groundwater Work Group s Initial Recommendations For Inclusion in Resource Protection Protocols 19