Norco City Council
January 19, 2022

Temescal Basin GSP 6-16
The cumulative storage declined slightly in the historical period (1993 through 2017) due to increased groundwater pumping and reduced imported water, with an average loss of storage of 194 acre-feet per year (AFY) in the Temescal Basin. Simulated groundwater storage mostly recovered during the one to two years following droughts, but still showed a general decrease in groundwater storage due to increased groundwater production over the same time. Under the future baseline conditions, the average annual change in storage in the Basin is expected to be nearly balanced, with a very slight decrease of 65AFY resulting in stable storage conditions for the Basin over the period. While the overall change in storage is slightly negative, the annual change in storage shows that expected inflows and outflows are evenly balanced. In the future growth plus climate change scenario, the average annual change in storage is an increase of 34 AFY, very slightly larger than baseline conditions as urban growth increases municipal irrigation return flows. Adaptive management will be key to respond to changing conditions including unexpected decreases to natural inflows or unexpected increases in groundwater pumping.

Given the relative stability of storage in the most recent period (2008 to 2017), and future simulations showing expected increases in storage, the current groundwater management practices will likely continue to increase groundwater storage on average and recover from short term droughts on the order of one to five years.

6.3.6. Minimum Threshold
Undesirable results relative to groundwater storage have not occurred in the Basin and numerical modeling of future conditions indicate that groundwater storage can continue to be operated within historical limits. Nonetheless, the potential for reduction of groundwater storage exists (probably involving disruption of imported water supply) and thus this section considers minimum thresholds for storage. According to GSP Regulations, the minimum threshold for storage is to be defined as the maximum groundwater volume that can be withdrawn without leading to undesirable results.

However, GSP Regulations allow the use of the groundwater level sustainability criteria (MTs and MOs) as a proxy for groundwater storage, provided that the GSP demonstrates a correlation between groundwater levels and storage. Groundwater levels and storage are closely related. This is demonstrated by comparison of groundwater level and storage trends, which reveal the same patterns of historical response to drought and recovery. The relationship of levels and storage is embodied in the calibrated numerical model.

The rationale for using groundwater levels as a proxy metric for groundwater storage is that the groundwater level MTs and MOs are sufficiently protective to ensure prevention of significant and unreasonable results relating to storage. In brief, groundwater level MTs have been defined to protect supply wells (see Section 6.2.6) and are based on the following:
• A broad geographic distribution of Key Wells that are representative of Basin production wells
• MTs that are based on historical minimum groundwater levels, consistent with analyses of storage change

Temescal Basin GSP 6-17
• Analysis of existing wells with construction information • MTs are relatively shallow; as shown in Table 6-1, all MTs are relatively shallow in comparison to production well depths
• Groundwater level MTs include two consecutive exceedances in each of two years, providing early warning for storage changes, while also involving sixty percent or more of the Key Wells in the Basin, thus involving a broad area, consistent with storage change
As a practical matter, the availability of groundwater storage will be constrained by water levels (including groundwater level proxies for depletion of interconnected surface water) and given all the above, the MTs for groundwater levels are more than sufficiently protective of groundwater storage.

To summarize for the Basin:

The Minimum Threshold for storage is fulfilled by the minimum threshold for groundwater levels. The Minimum Threshold for defining undesirable results relative to chronic lowering of groundwater levels is defined at each Key Well (two consecutive quarters in two years, providing early warning for storage changes, in 60 percent or more of the Key Wells).

The Sustainability Goal for the Basin includes an objective to provide reliable storage for water supply resilience during droughts and shortages. Use of groundwater levels as a proxy also fulfills that objective. No additional MT definition is needed.

6.3.6.1. Relationship of Minimum Threshold to Other Sustainability Indicators • Water Levels. The minimum thresholds for groundwater levels are protective of the beneficial use of the Basin – municipal and industrial water supply; therefore, these levels are protective of and serve as a proxy for groundwater storage and the provision of reliable storage for drought and shortage. • Seawater Intrusion. There is no possibility of seawater intrusion in the Basin.

Accordingly, there is no minimum threshold and no relationship with other minimum thresholds.
• Subsidence. Subsidence is linked to groundwater levels. Because the storage reduction minimum threshold would not cause water levels to drop below their minimum thresholds, it would not interfere with the subsidence minimum threshold.
• Water Quality. Maintenance of groundwater storage within historical ranges would minimize any effects on water quality relative to water quality minimum thresholds.

Groundwater quality issues in the Basin are associated primarily with salt and nutrient loading and not likely to be affected by groundwater storage within historical ranges.
• Interconnected Surface Water. The minimum thresholds for interconnected surface water are shallow groundwater levels in the southern portion of the Prado

Temescal Basin GSP 6-18
Wetlands. The storage reduction minimum threshold does not propose decreased groundwater elevations below historical levels, so groundwater levels are expected to remain within the historical range. This means that water table depths in the Prado Wetlands will remain within the historical range, which was adequate to maintain the vegetation in good health.

6.3.6.2. Effect of Minimum Threshold on Sustainability in Adjacent Areas As noted in Section 6.2.6.3, the Basin borders portions of the Bedford-Coldwater Basin to the south, the Riverside-Arlington Basin along the Arlington Gap to the east, the Chino Basin on the north, and Coastal Plain of Orange County Basin at the west where the Santa Ana River exists the Basin. The groundwater level MTs would support maintenance of groundwater levels above their respective MTs throughout the Basin. This in turn will support maintenance of groundwater levels and storage in all four neighboring basins.

6.3.6.3. Effect of Minimum Threshold on Beneficial Uses and Users Beneficial uses and users of groundwater storage include maintenance of interconnected surface water and associated GDEs and municipal, industrial and other groundwater users.

The MTs for groundwater levels are based on historical minima, which recognizes that groundwater has been and is being used reasonably for the range of beneficial uses even during droughts. The storage minimum threshold is consistent with the water level minimum threshold, which means that available storage will be adequate to supply beneficial uses as long as water levels remain above their minimum thresholds.

6.3.6.4. Relationship of Minimum Threshold to Regulatory Standards Other than SGMA, no federal, state or local standards exist for reduction of groundwater storage.

6.3.6.5. How Management Areas Can Operate without Causing Undesirable Results Management areas have not been defined for the Basin so the establishment of MTs has been consistently conceived and applied to the entire Basin.

6.3.6.6. How the Minimum Threshold will be Monitored
Monitoring for the groundwater levels MT, which is the proxy for storage, will be part of the GSA groundwater level monitoring program (see Chapter 7). Data and analytical results, including assessment of change in storage, will be presented in GSP Annual Reports.

6.3.7. Measurable Objectives
MOs would be defined as an operating range of groundwater storage, allowing changes in groundwater storage with varying hydrologic and surface water supply conditions and as with conjunctive management of surface water and groundwater. The groundwater level MTs provide a protective level that corresponds to the minimum threshold for storage, which would keep groundwater storage within the historical operating range. The Five-Year GSP Update could include consideration of using more of this storage locally as part of ongoing conjunctive use while also protecting shallow wells.

Temescal Basin GSP 6-19
The Measurable Objective for storage is fulfilled by the MT for groundwater levels, which maintains groundwater levels above the historical maximum groundwater depths in each Key Well (as quantified in Table 6-1).

Groundwater conditions with respect to depletion of groundwater storage are already sustainable. Therefore, no interim milestones are needed to achieve sustainability by 2042.

6.3.7.1. Discussion of Monitoring and Management Measures to be Implemented Monitoring and management actions to prevent chronic reduction of groundwater storage and to provide groundwater reserves for drought will be the same as those for maintenance of groundwater levels. No other specific management actions for storage have been identified and no specific implementation is warranted.

6.4. SEAWATER INTRUSION
Seawater intrusion does not occur in the Basin because of its inland location. According to the GSP Regulations, the GSP is not required to establish criteria for such undesirable results that are not likely to occur. Accordingly, the remaining discussion in this section does not address seawater intrusion.

6.5. LAND SUBSIDENCE
Subsidence has not been a known issue in the Basin and undesirable results have not been reported. Nonetheless, the potential has been recognized that subsidence could occur as a result of groundwater pumping and groundwater level declines, typically in areas underlain by thick layers of fine-grained alluvial sediments.

As described in Section 4.3, available information on vertical land displacement (subsidence) includes estimates from InSAR satellite data systems. InSAR data provides mapping of ground surface elevations across the Basin, presented at regular (typically monthly) intervals.

InSAR data are made available by DWR from the TRE Altamira InSAR Dataset with vertical displacement data beginning in June 2015 and in monthly intervals thereafter until September 2019. The accuracy of the InSAR ground surface elevation change estimates is reported to be ±16 millimeters (mm), or ±0.052 feet (Towill 2020). While these data do currently represent a relatively short period of record, the InSAR data do not show significant changes in ground surface elevation in the Basin. The Basin shows small rise and fall within the margin of error throughout. Given the short records of these datasets and small vertical displacements, these data have not been analyzed systematically to identify specific areas that might be subject to long-term subsidence. As datasets are updated, that may be warranted in the future.

Data are limited not only on groundwater-related subsidence, but also potentially associated pumping and groundwater levels. SGMA allows groundwater level data to be used as a proxy for subsidence; however, relationships between pumping, groundwater

Temescal Basin GSP 6-20
levels, and subsidence have not been determined to support that. Subsidence information from DWR InSAR data will be reviewed as it becomes available.

6.5.1. Description of Undesirable Results
Land subsidence is the differential lowering of the ground surface, which can damage structures, roadways, and hinder surface water drainage. Subsidence remains a potential risk and inelastic subsidence is irreversible. Potential undesirable results associated with land subsidence due to groundwater withdrawals include the following:
• Potential damage to building structures and foundations, including water facilities, due to variations in vertical displacement causing potential cracking, compromised structural integrity, safety concerns and even collapse. • Potential differential subsidence affecting the gradient of surface drainage channels, locally reducing the capacity to convey floodwater and causing potential drainage problems and ponding.
• Potential differential subsidence affecting the grade or drainage of other infrastructure such as railroads, roads, and sewers.
• Potential subsidence around a production well, disrupting wellhead facilities or resulting in casing failure.
• Potential non-recoverable loss of groundwater storage as fine-grained layers collapse.

None of these undesirable results has been observed in the Basin. However, subsidence may be subtle and cumulative over time. Accordingly, the potential for future subsidence cannot be ruled out if regional groundwater levels were to decline below historical lows and minimum thresholds.

6.5.2. Potential Causes of Undesirable Results
As described in Section 4.3, changes in ground surface elevations may be caused by regional tectonism or by subsidence related to declines in groundwater elevations due to pumping.

Regarding the former, the InSAR data shows a general rising trend in the western portion of the Basin suggesting possible regional tectonic rise. In contrast, inelastic subsidence associated with groundwater pumping and level declines would generally show a long-term downward trend, with greater subsidence occurring during times of groundwater level decline (e.g., drought) and a flattening trend with no recovery during times of rising groundwater levels and reduced pumping (e.g., wet years).

In brief, as groundwater levels decline in the subsurface, dewatering and compaction of predominantly fine-grained deposits (such as clay and silt) can cause the overlying ground surface to settle. Land subsidence due to groundwater withdrawals can be temporary (elastic) or permanent (inelastic). While elastic deformation is relatively minor, fully recoverable, and not an undesirable result, inelastic deformation involves a permanent compaction of clay layers that occurs when groundwater levels in a groundwater basin

Temescal Basin GSP 6-21
decline below historical lows. This causes not only subsidence of the ground surface, but also compaction of sediments and loss of storage capacity.

Given the above, the potential for problematic land subsidence is affected by the proportion, overall thickness, and configuration of fine-grained sediments (with greater proportions and thicknesses suggesting greater potential). Because of the variability of local sediments, subsidence also is likely to be geographically variable. Moreover, the potential for subsidence is affected by the history of groundwater level fluctuations, such that areas with previous groundwater level declines may have already experienced some compaction and subsidence.

The potential for subsidence is possible, especially in the deeper portions of the Basin where there is more pumping, but there is no indication that permanent inelastic subsidence has occurred.

6.5.3. Potential Effects on Beneficial Uses and Users
The lack of any reports of undesirable results is an indication of no noticeable effects.

However, there is a general awareness in the Basin of subsidence problems in the Central Valley that cause the above listed effects. Nonetheless, some subsidence could have occurred because of historical groundwater level declines without being noticed and could have contributed to drainage or flooding problems, which are also affected by multiple and sometimes more noticeable factors including variable weather, changes in streams and drainage systems, land use changes in the watershed, erosion and sedimentation.

Accordingly, continued tracking of subsidence is warranted.

6.5.4. Minimum Threshold
According to the GSP regulations Section 354.28(c)(5) the minimum threshold for land subsidence is defined as the rate and extent of subsidence that substantially interferes with surface land uses. This section first addresses the rate at which subsidence substantially interferes with surface land uses and then describes how available InSAR data can be used to measure rate and extent across the Basin.

The Minimum Threshold for subsidence is defined as a cumulative decline equal to or greater than one foot since 2015, which represents current conditions and the SGMA start date. This corresponds to a rate of decline equal to or greater than 0.2 feet in any five-year period.

The 1-foot criterion is reasonable based on standards for flooding and drainage and on empirical data for well casing collapse:
• In the southwestern part of the Sacramento Valley, where documented cumulative subsidence has reached several feet, video surveys of 88 undamaged wells and 80 damaged wells showed that casing damage was uncommon in wells where subsidence was less than 1 foot (Borchers and Carpenter 2014).

Temescal Basin GSP 6-22
• Ground floor elevations are recommended or required to be at least 1 foot above the Base Flood Elevation in some jurisdictions (see for example FEMA 2011 and City of Temecula 2020). Subsidence above 1 foot may cause some buildings to become flooded.
• The minimum freeboard along roadside ditches is often required to be 1 foot above the maximum anticipated water level (see for example San Diego County 2005).

Greater subsidence may cause sewer and stormwater flows to flow in unintended directions.

Subsidence impacts can be relatively rapid and noticeable. However, in the Basin any subsidence in the future is likely to be gradually cumulative as would be its undesirable results. Accordingly, the 0.2 feet per 5-year rate of decline is an appropriate criterion, with the understanding that it will be re-evaluated in the 2027 GSP Update.

Based on available data and using the above criterion, significant and unreasonable subsidence has not occurred since 2015 in the Basin. Moreover, it is unlikely that the criterion will be exceeded in the future as groundwater pumping will be constrained with the MT set for groundwater levels and storage.

The extent of cumulative subsidence across the Basin will be monitored using the InSAR satellite-based data that DWR has been providing on the SGMA Data Portal website. The data consist of a closely spaced grid of elevation points and are characterized by considerable “noise,” meaning that adjacent points often have very different readings at the scale of 1 to 2 inches. These data will be smoothed to provide results at a spatial scale at which subsidence would plausibly occur. These values for cumulative elevation change will then be compared annually with the minimum threshold criterion.

6.5.4.1. Relationship of Minimum Threshold to Other Sustainability Indicators Subsidence is closely linked to groundwater levels. It is unlikely that significant inelastic subsidence would occur if groundwater levels remain above historical levels, which have been used to define groundwater level MOs. In addition, the operationally defined MT levels will prohibit significant pumping if water levels decline below historical lows. Accordingly, the minimum threshold for groundwater levels is consistent with and supportive of the objective to prevent subsidence undesirable results.

The subsidence MT would have little or no effect on other MTs. Specifically, subsidence MTs would not result in significant or unreasonable groundwater elevations, would not affect pumping and change in storage, would not affect groundwater quality, or result in undesirable effects on connected surface water.

6.5.4.2. Effect of Minimum Threshold on Sustainability in Adjacent Areas As noted in Section 6.2.6.3, the Basin borders portions of the Bedford-Coldwater Basin to the south, the Riverside-Arlington Basin along the Arlington Gap to the east, the Chino Basin on the north, and Coastal Plain of Orange County Basin at the west where the Santa Ana River exists in the Basin. The groundwater level MTs would support maintenance of

Temescal Basin GSP 6-23
groundwater levels above their respective MTs throughout the Basin. This in turn will support maintenance of groundwater levels above historical minima and, thus, subsidence affecting other basins is not expected to occur.

6.5.4.3. Effect of Minimum Threshold on Beneficial Uses and Users Subsidence problems have not been reported in the Basin, but subsidence remains a potential undesirable result that may contribute incrementally to reduced drainage, increased flooding, or other undesirable results. The effects of establishing the numerical subsidence MT are beneficial because they support a greater chance of detecting subsidence, supporting management actions to maintain groundwater levels, and preventing significant subsidence.

6.5.4.4. Relationship of Minimum Threshold to Regulatory Standards There are no federal, state or local standards specifically addressing subsidence. There are standards for flood depth, floodplain encroachment, freeboard in ditches and canals and slopes of gravity-flow plumbing pipes. These vary somewhat from jurisdiction to jurisdiction, but they are generally similar and were used as the basis for selecting the MT.

6.5.4.5. How Management Areas Can Operate without Causing Undesirable Results Management areas have not been defined for the Basin so the establishment of MTs has been consistently conceived and applied to the entire Basin.

6.5.4.6. How the Minimum Threshold will be Monitored
The minimum threshold will be monitored using InSAR areal data. Cumulative subsidence will be monitored using the InSAR satellite-based geodetic data that DWR has been providing on the SGMA Data Portal website. The data are “raster” data sets consisting of a grid of elevation points spaced approximately 300 feet apart. The InSAR data will be evaluated to identify any occurrence and areal extent of subsidence. As data are provided over the next few years, this evaluation will involve review of temporal InSAR data to discern seasonal elastic fluctuations and potential inelastic declines. In addition, any areal extent will be examined; this may involve smoothing of elevation changes over the InSAR grid to summarize the results to a spatial scale at which subsidence would plausibly occur.

The cell values for cumulative elevation change will then be compared with the minimum threshold criterion.

6.5.5. Measurable Objectives
The Sustainability Goal includes the objective to prevent subsidence. Accordingly, the MO is zero subsidence. Undesirable subsidence results have not occurred, and accordingly, no interim milestones are defined.

6.5.5.1. Representative Monitoring
It is assumed that the InSAR subsidence monitoring programs will continue for the foreseeable future and InSAR data will be available from the DWR website. The GSP monitoring program for subsidence will involve annual download of InSAR data with analysis for signs of cumulative inelastic subsidence.

Temescal Basin GSP 6-24

6.5.5.2. Discussion of Management Actions to be Implemented Management actions to prevent subsidence will be coordinated with actions relative to maintenance of groundwater levels. These actions involve maintaining groundwater levels above historical low water levels and will prevent significant inelastic subsidence. No other specific management actions for subsidence have been identified and no specific implementation is warranted.

6.6. DEGRADATION OF WATER QUALITY
Degraded water quality can impair water supply and affect human health and the environment. Impacts to drinking water supply wells can result in increased sampling and monitoring, increased treatment costs, use of bottled water, and the loss of wells. As described in Groundwater Conditions Sections 4.5 and 4.6, elevated concentrations in drinking water of some constituents, such as nitrate, can adversely affect human health.

Impacts to agricultural supply can include reduced yields, the need to change irrigation methods/sources, and other economic effects. Discharge of degraded groundwater can harm ponds, wetlands, and associated ecosystems (e.g., eutrophication).

Consideration of the causes and circumstances of water quality conditions is important in the Basin because general mineral quality (e.g., TDS, etc.) is naturally poor throughout much of the Basin, has been poor for decades, and nonetheless has been used for beneficial purposes including irrigation, municipal, and domestic purposes. The main beneficial use in the Basin is municipal supply and Corona uses blending with imported water and treatment to meet federal, state, and local drinking water guidelines.

Sustainable management is about use and management of groundwater without causing undesirable results but does not necessarily include reversing natural undesirable conditions. According to SGMA (§10727.2(b)(4)), a GSP may—but is not required to— address undesirable results that occurred before and have not been corrected by the SGMA benchmark date of January 1, 2015.

Given all that, the sustainability goal—to protect groundwater quality—is not to reverse undesirable water quality conditions by 2042 but rather to prevent circumstances wherein future management activities might make water quality worse and insofar as possible to improve water quality in the long run. Implementation of management actions is recognized as needed now and, whether or not the results are perceptible in the short term, such actions will be helpful in the long term.

6.6.1. Potential Causes of Undesirable Results
The quality of groundwater in the Basin is characterized as somewhat mineralized, reflecting natural hydrogeologic processes (see Groundwater Conditions Section 4.4). Groundwater also has been affected by human activities including agricultural, rural, urban, and industrial land uses. While contaminant sources of groundwater quality degradation exist, these are effectively regulated as described in Groundwater Conditions Section 4.6 and regularly tracked as part of the GSA’s monitoring program.

Temescal Basin GSP 6-25
As described in the Groundwater Conditions section, total dissolved solids (TDS) and nitrate are constituents of concern for the Basin. While there are elevated natural background TDS concentrations in groundwater, TDS also is an indicator of human impacts including infiltration of urban runoff, agricultural return flows, and wastewater disposal. Natural nitrate levels in groundwater are generally very low, and elevated concentrations are associated with agricultural activities, septic systems, landscape fertilization, and wastewater treatment facility discharges.

Other constituents have been documented (see Groundwater Conditions Section 4.8) but occurrences of these are either under regulation by RWQCB (e.g., perchlorate) or are naturally occurring with no recent exceedances of MCLs and limited potential for mobilization due to management actions (e.g., arsenic, chromium, iron, and manganese).

6.6.2. Description of Undesirable Results
The processes and criteria relied on to define Undesirable Results included review of available data and information summarized in the Plan Area and Groundwater Conditions sections and discussions with Temescal Basin stakeholders and local agency representatives.

Undesirable Results are defined in the GSP Regulations (§354.26) as occurring when significant and unreasonable effects for any of the sustainability indicators are caused by groundwater conditions occurring throughout the Basin. The GSA is not responsible for local problems or degradation caused by others. While the Basin includes regulated facilities with soil and groundwater contamination (see Groundwater Conditions Sections 4.4 and 4.7), these sites are under regulatory oversight by State agencies; the GSA does not have the mandate or authority to duplicate these programs. Nonetheless, the GSA plans to regularly cooperate with these agencies and check regulator files regularly as part of its water quality monitoring program. In addition, this GSP avoids management actions that would spread groundwater contamination through managed aquifer recharge, pumping, or other activities.

In fact, the GSA agencies have historically conducted management actions and programs (often in cooperation with other agencies) to improve groundwater quality. These activities have included treatment of groundwater and imported surface water for municipal use (which improves wastewater quality), wastewater treatment plant improvement and water recycling, and programs to reduce urban and agricultural salt and nutrient loading.

6.6.3. Potential Effects on Beneficial Uses and Users
Groundwater is a source of supply in the GSP Area and supports a range of beneficial uses:
agricultural, municipal, rural, and environmental. Beneficial uses of water and respective water quality objectives are defined by the RWQCB in the Santa Ana Basin Water Quality Control Plan (Basin Plan). For TDS and nitrate, these are tabulated in the GSP Groundwater Conditions (Section 4.5 Key Constituents of Concern); this section indicates that water quality in the Basin is naturally mineralized and affected by human activities and has not been shown to change significantly. It is recognized that groundwater has been and is being used for the range of beneficial uses with reasonable accommodation by users. Blending

Temescal Basin GSP 6-26
and treatment of groundwater for municipal supply has been successful to provide drinking water to the Basin. This recognition does not preclude or ignore a desire by the community or intent of local agencies including the GSA to improve local groundwater quality.

6.6.4. Sustainable Management Criteria for Groundwater Quality The definition of an Undesirable Result due to degraded water quality—TDS and nitrate concentrations—was evaluated in the context of regulatory objectives in the Basin.

GSP regulations require that the minimum threshold for degraded water quality be based on “the number of supply wells, a volume of water, or a location of an isocontour that exceeds concentrations of constituents determined by the agency to be of concern for the basin” (§354.28(4)). The number of supply wells are considered here for the minimum threshold.

This is because the issues of concern in the Basin are focused on regional nitrate and salt loading, data are insufficient to define plumes or volumes of water, and the position of an isocontour is not applicable.

6.6.4.1. Temescal Water Quality Monitoring Program
The GSA agencies established a water quality monitoring program for the protection of beneficial uses, understanding of human and natural factors that affect water quality, and support for groundwater management decisions. The City of Corona (Corona) has been the primary agency implementing this program in the Basin and regularly monitors groundwater production wells as well as select dedicated monitoring wells. The network of wells historically has been focused on the Channel Aquifer where Corona pumps most of its water for municipal supply. The wells generally are sampled quarterly with lab analysis for general minerals, physical parameters, and selected constituents of concern. Accordingly, this data set can be used to detect a range of problems quickly, to track trends, allow geochemical investigation, and support focused management actions.

In addition, the GSA will regularly compile, reviews, and summarizes all available information on water quality in the Basin from the groundwater ambient monitoring program (GAMA) Groundwater Information System (SWRCB 2020b).

Limitations of this data set include the uneven and potentially shifting distribution of sampled wells across the Basin, lack of information on the vertical zone being sampled (well construction information), relatively less frequent sampling schedule and absence of historical record, variable data availability on specific constituents and parameters, and multiple sources of information from programs with differing objectives and procedures.

These limitations present significant uncertainties to the GSA and stakeholders who are required to establish quantitative, measurable criteria and then comply with them, with real-world consequences.

6.6.5. Minimum Thresholds
Minimum Thresholds (MTs) are presented for nitrate and TDS using the best available information, namely data generated by the Water Quality Monitoring Program and compiled data. As summarized above, the limitations of this data set are recognized, and

Temescal Basin GSP 6-27
additional investigations and monitoring program improvements will be presented in this GSP for planned implementation. With adaptive management in mind, MTs may be revised to rely more on the GSA in the future as needed.

The MTs for nitrate and TDS quantify current conditions (2015 through 2019) based on available monitoring data. Water quality monitoring serves two useful purposes. First, it will eventually confirm whether concentrations begin leveling off as intended. Second, it can detect local sources of degradation that impact groundwater quality more strongly and rapidly than the slow, dispersed loading from agricultural activities. Early detection of local impacts can enable appropriate actions to halt further contamination before the impacts become severe or widespread.

6.6.5.1. Minimum Threshold for Nitrate (NO3)
Table 6-2 summarizes current conditions for nitrate in reference to the maximum contaminant level (MCL) for nitrate as nitrate (NO3) in drinking water, 45 mg/L, which also is the Basin Plan Objective for municipal use. Current conditions are expressed in terms of the percent of wells with concentrations over 45 mg/L. To compute the percent of wells, nitrate sampling results were compiled for each well over the period 2015 through 2019. For wells with one sample, the single value was used; for wells with two samples, the average value was used; and for wells with three or more values, the average value was used. Accordingly, each well was represented by one value. This was followed by computation of the percentage of wells with concentrations exceeding 45 mg/L.

This process of summarizing current conditions makes use of all available data. It also is recognized that the data are not representative of water supply conditions throughout the Basin because the geographic distribution of wells is uneven and information from shallow and deep wells are combined. Monitoring program improvements will be implemented as part of the GSP to improve the data set (see Section 6.6.6.2) and provide a more reasonable basis for sustainability criteria.

Table 6-2. Summary of Current Conditions for Nitrate (NO3) and TDS Water Quality
Parameter
Minimum
Threshold (MT)
Total
Wells
Number of Wells
Exceeding MT
Percent of Wells
Exceeding MT
Nitrate as Nitrate (NO3) 45 mg/L 24 12 50 percent
TDS 1,000 mg/L 23 6 26 percent
As documented in Table 6-2, there are wells in the Basin yielding water with nitrate concentrations exceeding the MCL. While recognizing the number of wells affected by high nitrate concentrations, there has been historical and ongoing groundwater use with reasonable accommodation by users and accordingly, these conditions are considered sustainable.

Temescal Basin GSP 6-28
Despite the significant uncertainties, the following MT is presented as a starting point for maintenance and planned improvement of groundwater quality for the 2042 deadline for sustainability.

The Minimum Threshold for nitrate is defined initially as the percentage of wells with concentrations exceeding the nitrate MCL (45 mg/L) based on current conditions (2015-2019).

Given the above definition, the MT for nitrate is expressed in Table 6-2. This MT refers to the numeric MCL and Basin Plan objective, honors the non-degradation policy, and quantifies current conditions based on available data. As described in the following section, Measurable Objectives, the approach is to implement management actions that will maintain or reduce nitrate concentrations in the future.

6.6.5.2. Minimum Threshold for Total Dissolved Solids
Table 6-2 summarizes current conditions for TDS with reference to the 1,000 mg/L secondary maximum contaminant level (SMCL). This value is far from ideal, but reflects the widespread conditions of elevated TDS concentrations in groundwater. The main beneficial use in the Basin is municipal supply and Corona uses blending with imported water and treatment to meet federal, state, and local drinking water guidelines.

As with nitrate, computation of the percent of wells in Table 6-2 involved compilation of sampling results for each well over the period 2015 through 2019. For wells with one sample, the single value was used; for wells with two samples, the average was used; and for wells with multiple values, the average was used, such that each well was represented by one value. This was followed by computation of the percent of wells with concentrations exceeding 1,000 mg/L.

This process makes use of all available data. The data are not representative of water supply conditions throughout the Basin because the depths and geographic distribution of wells is uneven. Monitoring program improvements will be implemented as part of the GSP to improve the data set and provide a more reasonable basis for sustainability criteria.

Despite the uncertainties, the following MT is presented as a starting point for maintenance and planned improvement of groundwater quality for the 2042 deadline for sustainability.

The Minimum Threshold for TDS is defined initially as the percentage of wells with concentrations exceeding the TDS value of 1,000 mg/L based on current conditions (2015-2019).

As with nitrate, this MT is presented with full recognition of data gaps and uncertainties, and with the commitment incorporated in this GSP to investigate nitrate and salt loading under current conditions and to expedite management actions for reduction of nitrate and salt loading.

Accordingly, the TDS MT is expressed in Table 6-2. This MT refers to the numeric Basin Plan objective, honors the non-degradation policy, and quantifies current conditions based on available data. Given historical and ongoing groundwater use, these conditions are

Temescal Basin GSP 6-29
considered sustainable. As described in the following section, Measurable Objectives, the approach is to implement management actions that will maintain or reduce nitrate concentrations in the future.

6.6.5.3. Relationship of Minimum Threshold to Other Sustainability Indicators Three of the other sustainability indicators (groundwater level declines, storage depletion, subsidence) are directly linked to groundwater levels, while the sustainability indicator for connected surface water-groundwater dependent ecosystems is related to a rate or volume of surface water depletion, also linked to groundwater levels. The MTs for water quality are not known to be directly related to specific groundwater levels or fluctuations in groundwater levels. Nonetheless, general relationships are recognized, for example that contaminants may be mobilized by changing groundwater levels or flow patterns.

Accordingly, the water quality MTs will help guide potential projects that alter groundwater levels or flow.

6.6.5.4. Effect of Minimum Threshold on Sustainability in Adjacent Areas The Basin borders portions of the Bedford-Coldwater Basin to the south, the RiversideArlington Basin along the Arlington Gap to the east, the Chino Basin on the north, and Coastal Plain of Orange County Basin at the west where the Santa Ana River exists in the Basin. The MTs for the Basin represent current conditions; establishment of MTs and maintenance of such conditions, which reflect native conditions, would not affect the ability of the neighboring basins to achieve or maintain sustainability.

As consideration beyond the requirements of this section, some management actions to improve groundwater quality in the Basin (for example enhancing outflow of poor-quality groundwater) could potentially have adverse impacts downstream. However, potential impacts of management actions and projects will be addressed through the California Environmental Quality Act (CEQA). Overall improvement of the Basin groundwater quality through other management actions (e.g., increased CVP percolation with maintenance of outflow) would be beneficial.

6.6.5.5. Effect of Minimum Threshold on Beneficial Uses and Users The establishment of the MTs reflects the current condition of the Basin relative to nitrate and TDS concentrations, insofar as available data and monitoring allow us to know.

Establishing the MTs represents no change and recognizes that groundwater has been and is being used reasonably for the range of beneficial uses. The MTs represent a quantified starting point for protection of groundwater quality and for projects and management actions to improve groundwater quality, consistent with a best management practices approach.

6.6.5.6. Relationship of Minimum Threshold to Regulatory Standards The MTs have been established with direct reference to regulatory standards, most notably the Maximum Contaminant Levels, drinking water standards set by the State of California, while recognizing that current nitrate and TDS concentrations in many wells do not meet regulatory standards. It should be noted all water delivered to users in the Basin met all drinking water standards, as achieved through blending and treatment.

Temescal Basin GSP 6-30

6.6.5.7. How Management Areas Can Operate without Causing Undesirable Results Management areas have not been defined for the Basin so the establishment of MTs has been consistently conceived and applied to the entire Basin.

6.6.5.8. How the Minimum Threshold will be Monitored
The GSP is using the best available information, namely data from the GSA’s Water Quality Monitoring Program and available data from GAMA. The GSA’s Water Quality Monitoring Program, along with its regular sampling schedule, historical records, and data on specific constituents and parameters will be the primary basis for MT tracking with reference to GSP 5-year updates.

6.6.6. Measurable Objectives
The sustainability goal is to protect groundwater quality, with general objectives of maintaining groundwater quality, preventing circumstances where future management activities might make water quality worse, and improving groundwater quality in the long run. In setting Measurable Objectives (MOs), a key issue is legacy loading, where the amount of historical loading is not known nor is the rate at which it is moving down to affect deep pumping zones. Because of the uncertainties associated with legacy loading, the use of water quality monitoring to track or verify sustainability needs to be tempered with a broad margin of operational flexibility. This margin should acknowledge the possibility (and even likelihood) that monitoring could indicate undesirable results—those stemming from past practices—while present reductions in loading are not yet perceptible.

6.6.6.1. Description of Measurable Objectives
Measurable Objectives are defined in this GSP using the same metrics and monitoring data as used to define Minimum Thresholds and are established to maintain or improve groundwater quality. Given the significant uncertainties presented by legacy loading and by data limitations, a reasonable margin of safety includes the possibility of “negative” monitoring results while positive progress is being made.

The Measurable Objective for nitrate is defined as maintaining or reducing the percentage of wells with average concentrations exceeding the nitrate MCL (45 mg/L) based on conditions documented in GSP 5-year updates.

The Measurable Objective for TDS is defined as maintaining or reducing the percentage of wells with average concentrations exceeding the TDS value of 1,000 mg/L based on conditions documented in the GSP 5-year updates.

Measurable Objectives will be evaluated in increments of five years and the numeric values will be presented with comparison to the Current Conditions. This comparison will be discussed in the context of actual progress in implementing measures to improve monitoring and management.

6.6.6.2. Discussion of Monitoring and Management Measures to be Implemented The strategy of this GSP is to identify and implement monitoring and management measures to reduce nitrate and salt loading. Monitoring and management actions already undertaken

Temescal Basin GSP 6-31
are summarized in Plan Area Section 2 and would be continued, most notably including the following:
• Corona water treatment that continues to use imported water and thereby improve wastewater quality.
• Corona wastewater treatment improvements (nitrate reduction) and water recycling.

Additional management measures include the following:
• Development of a stormwater recharge program including cooperation with local agencies to prepare a Storm Water Resource Plan, with identification of opportunities to increase recharge using local storm runoff. • Analysis of Basin outflows relative to salt management. • Enhanced outreach to Temescal Basin stakeholders (including disadvantaged communities) on groundwater quality issues.

6.6.6.3. Description of Reasonable Pathway
Implementation of this GSP will include regular updates on a five-year basis. This will include evaluation of Measurable Objectives with comparison to Current Conditions (2015-2019).

Because groundwater quality conditions are considered sustainable, interim milestones toward sustainability are not relevant. These comparisons will be discussed in the context of actual progress in implementing measures to improve monitoring and management.

A first step along the pathway will be analysis of the triennial data set used to establish criteria. A subset of the wells will be selected considering factors such as: uniform geographic representation, availability of well depth information, and continuity from one triennial period to the next. This first step will be completed during the first five years of GSP implementation.

The Management Actions and Implementation Plan sections of this GSP are intended to provide additional detail on the scope, scheduling, and estimated costs of the measures to be implemented.

6.7. DEPLETIONS OF INTERCONNECTED SURFACE WATER
This section builds and extends the discussion of interconnection of surface water and groundwater presented in in Section 4. That section provided information on surface watergroundwater connections (both seasonally and with wet years and drought), identification of potential groundwater dependent ecosystems (GDEs), distribution of riparian vegetation, and assessment of animal species that rely on groundwater-supported streamflow. Briefly, the analysis found that the only location within the Basin where pumping might affect surface flow or vegetation is along the southern edge of Prado Wetlands. Small patches of riparian vegetation in canyons where tributary streams enter the west side of the Basin are supplied by groundwater discharging from bedrock uplands and are not affected by pumping in the Basin. No isolated springs or seeps are located in the Basin.

Temescal Basin GSP 6-32

6.7.1. Description of Undesirable Results
If a stream is hydraulically connected to groundwater, pumping from nearby wells can reduce the amount of stream flow by intercepting groundwater that would have discharged into the stream or by inducing seepage from the stream. Undesirable results associated with stream flow depletion include reduced quality and quantity of aquatic and riparian habitats and reduced water supply to downstream users. Areas of interconnected surface water can also contain riparian vegetation that relies on shallow groundwater as an important source of water. Conceptually, adverse impacts for stream and riparian habitat can result from decreased rainfall, decreased stream flow, and lowered groundwater levels. These variables are highly correlated in time: droughts include rainfall reductions, decreased stream flows, and lowered groundwater levels at a time when habitat impacts are usually the most severe. Furthermore, droughts and wet periods are a natural feature of California’s climate and are associated with waxing and waning of habitat conditions.

6.7.2. Potential Causes of Undesirable Results
Depletion of interconnected surface water by groundwater pumping can impact a variety of beneficial uses of surface water. A systematic evaluation of each potential impact is warranted, including impacts on downstream water users, and plants and animals that rely on flow or shallow water table conditions along streams.

6.7.2.1. Surface Water Users
There are no known diverters of surface water from Temescal Wash in the Basin. However, the Wash is tributary to the Santa Ana River, which is a source of supply to Orange County Water District downstream of Prado Dam. Pursuant to a 1968 agreement with Western Municipal Water District (WMWD), the Corona is required to discharge 1,625 acre-feet (AF) of water from Temescal Wash into the Prado Wetlands. That amount is equivalent to a continuous flow of 2.25 cubic feet per second (cfs) and has always been met by discharges of recycled water from Water Reclamation Facility 1 (WRF-1) to the lined reach of Temescal Wash upstream of the wetlands.

Groundwater discharge into the Prado Wetlands is apparently not viewed as a significant source of supply to downstream surface water users, based on active efforts over the past two decades to eliminate groundwater discharge into the wetlands from the Chino Basin.

The Regional Water Quality Control Board mandated that the Chino Basin be operated to achieve “hydraulic control”, which means eliminating groundwater discharge into the Wetlands (WEI 2019). The objective is to prevent saline groundwater in the area from seeping into the Santa Ana River. Beginning in 2000 and increasing in stages since then, the Chino Desalter Wells now pump approximately 30,000 AFY of groundwater, most of which would otherwise discharge into the Prado Wetlands. This decrease in groundwater inflow has been offset by increases in surface water inflow, primarily discharges of reclaimed water from treatment plants along the Santa Ana River and its tributaries.

The expectation that flow requirements of Prado Wetlands and downstream water users will be met by surface inflows to the Wetlands rather than groundwater inflow is echoed in the Upper Santa Ana River Habitat Conservation Plan (SARHCP, ICF 2020). The plan notes

Temescal Basin GSP 6-33
that simulations using a regional groundwater model project about 5 feet of groundwater decline in the Prado Wetland area by 2030. However, no mitigation measures or management actions related to groundwater are included in the plan.

Groundwater discharge from the Basin into the Prado Wetlands is not expected to decrease in the future because groundwater levels are not expected to decrease. This assertion stems from the lack of long-term declines in water levels since at least 2005 (see Figure 4-23) and the selection of minimum historical water levels as the minimum thresholds for water levels in this GSP (see Section 6.2.6). However, the preceding discussion indicates that an increase in groundwater pumping resulting in slightly lowered groundwater levels and reduced groundwater discharge into Prado Wetlands would not cause an undesirable result for downstream water users.

6.7.2.2. Animals Dependent on Groundwater
The primary animal species that depend on groundwater in the Basin are birds that inhabit riparian vegetation in the Prado Wetlands, including several listed species. The nexus between groundwater and those species is via the extent and health of riparian vegetation, discussed below.

6.7.2.3. Riparian Vegetation
The beneficial use of interconnected surface water with the greatest potential to be impacted by groundwater pumping is riparian vegetation along the southern edge of the Prado Wetlands, where the Basin groundwater discharges into the Wetlands. As described above (Section 6.7.2.1 Surface Water Users), the Wetlands are presently sustained almost entirely by surface water inflow rather than groundwater discharge. Although substantial or long-term decreases in groundwater discharge from the Basin into the Prado Wetlands are not expected, they would tend to cause vegetation die-back along the southern fringe of the Wetlands by lowering the water table to a depth beyond the reach of vegetation roots.

6.7.3. Definition of Undesirable Results
The Sustainability Goal includes an objective to support beneficial uses in the Basin, and specifically those related to interconnected surface water. Consistent with that objective, undesirable results of excessive depletion of surface water are:

Riparian vegetation die-back or mortality during droughts of a magnitude that disrupts ecological functions or causes substantial reductions in populations of riparianassociated species.

6.7.4. Potential Effects on Beneficial Uses and Users
The analysis presented in this section demonstrates that groundwater conditions are currently sustainable with respect to interconnected surface water and GDEs. There are no users of surface water in the Basin, and the needs of Santa Ana River users downstream of the Basin appear to be met by surface inflows to the Prado Wetlands and past Prado Dam.

Although lowering of the water table in the Prado Wetlands could stress or kill riparian

Temescal Basin GSP 6-34
vegetation, the extent and health of riparian vegetation do not appear to be correlated with groundwater levels in water supply wells in the Basin (see Section 4.10.4).

6.7.5. Sustainable Management Criteria for Interconnected Surface Water SGMA requires that the minimum threshold for depletions of interconnected surface water shall be the rate or volume of surface water depletions caused by groundwater use that has adverse impacts on beneficial uses of the surface water and may lead to undesirable results (§354.28(c)(6)). However, GSP Regulations allow GSAs to use groundwater elevation as a proxy metric for any of the sustainability indicators when setting minimum thresholds and measurable objectives (23 CCR § 354.28(d) and 23 CCR § 354.30(d)).

It would be difficult to define a minimum threshold in terms of flow depletion in this Basin because phreatophytic riparian vegetation in the Prado Wetlands is more dependent on surface inflows from outside the Basin (that is, from the Santa Ana River) than from groundwater discharge within the Basin. Also, groundwater does not need to discharge at the land surface to support vegetation; it only needs to rise up to the root zone. Thus, it is reasonable to define the minimum threshold in terms of water levels instead of flow.

6.7.6. Minimum Threshold
Given the above, the minimum threshold is defined here by groundwater levels. As noted previously, wells in the groundwater level monitoring program are production wells with relatively deep screens that have not been sited and designed for tracking surface watergroundwater interactions or water table depths in areas of riparian vegetation. The lack of such shallow monitoring wells is a data gap and a source of uncertainty. Hence, the minimum threshold described here is initial. Nonetheless, it is intended to be protective of GDEs until the monitoring program can be refined to better represent water-table depths along the southern edge of the Prado Wetlands.

Therefore, in the Basin:

The Minimum Threshold for depletion of interconnected surface water is the amount of depletion that occurs when the depth to the water along the southern edge of the Prado Wetlands is greater than 15 feet for a period exceeding one year.

This threshold corresponds approximately to the maximum depth to water measured in shallow monitoring wells in the northern part of the Prado Wetlands.

Undesirable results are considered to commence if the water-table depth along the southern edge of the Prado Wetlands declines below the MT and the decline correlates with declining water levels in production wells in the Basin.

6.7.6.1. Relationship of Minimum Threshold to Other Sustainability Indicators • Groundwater Levels. The water level MTs are set to equal the minimum historical water levels in existing monitored wells, all of which are over 1 mile from the Wetlands. The now-destroyed Butterfield Park Well was much closer to the Wetlands than the other monitored wells, and its water levels indicated that

Temescal Basin GSP 6-35
groundwater elevations and depths to water decreased continuously from the production wells in the center of the Basin to the Prado Wetlands. Assuming hydraulic connection between those two locations, the water level MT should prevent the water table at the edge of the Wetlands from declining below the historical minimum. Water levels in shallow monitoring wells in the northern part of the Prado Wetlands either did not decline much during the 2013 to 2015 drought or declined slightly to reach their lowest historical levels. There did not appear to be widespread die-back of vegetation in the Prado Wetlands during the 2013 to 2015 drought. Historical aerial photos confirmed a substantial reduction in riparian tree/shrub canopy coverage along the lowermost reach of Temescal Wash, where it enters the Prado Wetlands (a roughly 8,300-foot reach from North Lincoln Avenue to below West Rincon Avenue) (McMichael 2021). However, the decrease in vegetation appeared to start around 2009 (before the drought) and has been attributed to decreased base flow in Temescal Wash (McMichael 2021). The period of record for the Butterfield Park Well is only 2011 through 2017, so it is not possible to correlate the change in vegetation with groundwater levels over the entire period of interest. However, the MT for interconnected surface water is consistent with the water-level MT in that they both avoid water levels lower than historical minimum levels, which in most wells occurred during the 2013 to 2015 drought. Thus, the two MTs are consistent, and managing for one would not impact managing for the other.
• Groundwater Storage. The minimum threshold for interconnected surface water would similarly be consistent with the minimum threshold for groundwater storage near GDE reaches, because the latter is functionally the same as the minimum threshold for water levels.
• Seawater Intrusion. Seawater intrusion would not occur in the Basin due to its inland location. No minimum threshold was defined and there is no consistency issue.
• Land Subsidence. Significant land subsidence is only likely to occur with groundwater levels below historical minimum levels. The levels specified as minimum thresholds for interconnected surface water are thought to be within the historical range and thus unlikely to cause subsidence. • Water Quality. Water quality issues in the Basin are primarily associated with dispersed loading of nitrate and salinity and long-term increases in ambient concentrations of those constituents. Those processes are generally independent of groundwater levels.

6.7.6.2. Effect of Minimum Threshold on Sustainability of Adjacent Areas The Basin is separated from the Bedford-Coldwater Basin by a reach of Temescal Wash that flows over bedrock. Changes in groundwater-surface water interactions in the Basin would not propagate upstream to the Bedford-Coldwater Basin. The hydraulic connection between the Basin and the Arlington Basin is small and far from the Prado Wetlands. Water levels at

Temescal Basin GSP 6-36
the edge of the Wetlands would not affect flow across that boundary. The Chino Basin abuts the Basin beneath the Prado Wetlands. The Chino Basin does not rely on northward flow of groundwater from the Basin. On the contrary, basin operation in the Chino Basin seeks to minimize southward groundwater flow. The adjacent area with the greatest potential to be affected is Orange County downstream of Prado Dam. However, those areas are not heavily reliant on groundwater outflow from the Basin (see Section 6.7.2.1 Surface Water Users), and the minimum threshold for interconnected surface water would ensure that outflow does not drop below the historical minimum in any case.

6.7.6.3. Effect of Minimum Threshold on Beneficial Uses Surface diversions are not a source of supply in the Basin; all water uses are supported by imported water or groundwater. With respect to groundwater, this GSP does not propose decreased groundwater elevations below historical levels, so groundwater levels are expected to remain within the historical range. This means that water table depths in the Prado Wetlands will remain within the historical range, which was adequate to maintain the vegetation in good health.

Riparian vegetation along Wardlow Wash would not be adversely affected if groundwater levels dropped to the groundwater elevation MT or the interconnected surface water MT because Wardlow Wash is far from the location of intensive pumping in the Basin (the Channel Aquifer) and on the opposite side of one or more faults that appear to sustain high groundwater levels along Wardlow Wash.

6.7.6.4. Relationship of Minimum Threshold to Regulatory Standards Other than SGMA, there are no local, state, or federal regulations that specifically address stream flow depletion by groundwater pumping. The California and federal Endangered Species Acts protect species listed as threatened or endangered, including least Bell’s vireo and Southwestern Willow Flycatcher. The minimum threshold for depletion of surface water is designed to prevent groundwater conditions from impacting those species beyond the level of impact that has historically occurred.

6.7.6.5. How the Minimum Threshold Will Be Monitored
There presently are no shallow monitoring wells in the southern part of the Prado Wetlands; all of them are in the northern part. This is a data gap that will be filled during the first 5- year implementation period of this GSP. In the meantime, if water levels in the Basin unexpectedly drop below their MT elevations, the levels will be evaluated in conjunction with shallow-well water levels in the northern part of the Wetlands to estimate whether the depth to water near the southern edge of the Wetlands might be increasing to more than 15 feet.

6.7.7. Measurable Objective
The Measurable Objective for interconnected surface water is a depth to the water table along the southern edge of the Prado Wetlands that is less than the MT of 15 feet.

Groundwater conditions with respect to interconnected surface water and most GDE

Temescal Basin GSP 6-37
parameters are currently sustainable. Therefore, no interim milestones are needed to achieve sustainability at this time.

6.7.8. Data Gaps
The primary data gap for interconnected surface water is the lack of shallow wells to monitor water table depth along the southern edge of the Prado Wetlands. Orange County Water District (OCWD) recently installed several shallow monitoring wells in the southern Prado Wetlands and has plans to install more in the near future. Water levels from these OWCD wells and additional wells that will be installed by the GSA (see Chapter 8) will be incorporated into the GSAs monitoring program as they become available, which will fill this data gap.

6.7.8.1. Discussion of Monitoring and Management Measures to be Implemented The primary management action that will be implemented during the first 5-year implementation period will be to install two to four shallow piezometers along the southern edge of the Prado Wetlands, between the wetlands and the major production wells in Corona. These would consist of 2-inch polyvinyl chloride (PVC) casings and screens extending below the water level at the time of drilling to capture seasonal and long-term fluctuations in shallow groundwater levels. Reference point elevations at the well heads will be surveyed so that water levels can be tied to sea level.

Basin pumping and water levels are not expected to adversely impact riparian vegetation in the Prado Wetlands. In the unlikely event that such an impact does occur, Corona has various potential options available that could be temporarily implemented to minimize or mitigate impacts during droughts. These include reducing total pumping, shifting pumping to wells farther from the Wetlands, or temporarily increasing reclaimed water discharges down Temescal Wash to the Wetlands. Corona will select the most effective response based on the circumstances of the impact.

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Key Wells
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Temescal Basin GSP 7-1

MONITORING NETWORK
The overall objective of the monitoring network for this Groundwater Sustainability Plan (GSP) is to yield representative information about water conditions in the Temescal Subbasin (Basin) as necessary to guide and evaluate GSP implementation. Specifically, monitoring network objectives are to:
• Build on the existing monitoring network data to represent the entire Basin, • Reduce uncertainty and provide better data to guide management actions, document the water budget, and better understand how the surface water/groundwater system works,
• Monitor groundwater conditions relative to sustainability criteria, and • Identify and track potential impacts on groundwater users/uses and better communicate the state of the Basin.

With the intent to provide sufficient data for demonstrating short-term, seasonal, and longterm trends in groundwater and related surface conditions, this GSP builds on existing monitoring programs (summarized in Chapter 2, Plan Area) that provide historical information and a context for monitoring. Data gaps are addressed in terms of information needed for understanding the basin setting, evaluation of the efficacy of GSP implementation, and the ability to assess whether the Basin is being sustainably managed.

This GSP section describes the monitoring network as enhanced to fulfill Sustainable Groundwater Management Act (SGMA) requirements and explains how it will be implemented. This includes description of the monitoring protocols for data collection, the development and maintenance of Temescal Groundwater Sustainability Agency (GSA) data management system (DMS), and the regular assessment and improvement of the monitoring program.

7.1. DESCRIPTION OF MONITORING NETWORK
The monitoring network for GSP implementation has been established to document groundwater and related surface conditions as relevant to the sustainability indicators:
groundwater levels, storage, land subsidence, water quality, and interconnected surface water6. The components of the monitoring network are presented in Table 7-1. 6 Seawater intrusion is noted, but no risk of seawater intrusion exists in this inland basin.

Table 7.1 - Temescal GSP Monitoring Program Summary
Monitored Variable Type of Measurement Locations Data Interval Data Collection Agency Database Storage Agency Notes Groundwater levels
Temescal Basin Depth to water, feet 37 monitored wells
(see Table 7-2)
Continuous to
Annual
City of Corona Temescal GSA Data from all sources compiled into unified groundwater elevation database
Groundwater storage
Rainfall Rain gauge, daily total, inches Lake Elsinore, Santiago Peak, and Riverside
Daily and
Monthly
NOAA, Orange County, and UC
Riverside CIMIS
Temescal GSA Download from web annually for annual water budget and model update
Rainfall (Interpolated) Interoplated spatially from point data Basin-wide PRISM Climate Group Temescal GSA Rainfall gauges are not within the basin, and PRISM data helps interpolate in regions with climatic variation
Reference ET (ET0) Daily ETo, inches Lake Elsinore and Riverside Daily NOAA, UC Riverside CIMIS DWR Download from web Stream flow Daily average flow, cfs Two active USGS gages near Temescal Daily USGS USGS Download from web Wastewater pond water budgets WRF effluent discharge, evaporation, percolation, AF
Corona Monthly City of Corona Temescal GSA
Wastewater/ Recycled Water
percolation
WRF/RW percolation volume, AF Corona Monthly City of Corona Temescal GSA Recycled water use Recycled water delivery, AF Basin-wide Monthly City of Corona Temescal GSA Recycled water use is a relatively small but increasing supply Imported Water Volume imported water AF Imported to Temescal Monthly City of Corona Temescal GSA Crop patterns Map of farmland use by category Basin-wide Annual DWR DWR Field scale annual agricultural land use mapping data from remote sensing
Land Use Maps Maps of Land Use Basin-wide DWR (2014) and Riverside County (1993 and 2000)
DWR and Riverside County DWR data is statewide
Municipal Water Use Metered water use by sector Corona, Home Gardens and Norco Monthly City of Corona, Norco Temescal GSA Annual data reported in Annual Report: CVP, groundwater, recycled water use (AFY)
Groundwater pumping
Community Water Systems Estimated Basin-wide Annual
DDW
Groundwater Production Annual Volume, AFY Basin-wide Annual City of Corona Western Municipal Water District as Watermaster and Temescal GSA
Rural domestic, commercial,
industrial
Estimated Basin-wide Annual City of Corona Western Municipal Water District as Watermaster and Temescal GSA
Annual estimates provided in water budget updates of Annual Report Subsidence
Subsidence InSAR satellite mapping of ground
displacement
Basin-wide Annual change DWR (InSAR) DWR SGMA Data Portal Download annually, smooth InSAR raster data sets (see Section

4.2.3.1), compare cumulative elevation change since 2015 against Minimum Threshold criterion.

Groundwater quality
Groundwater Quality Major and minor ions and
contaminants
27 currently monitored wells Quarterly/ SemiannualCity of Corona , DDW, RWQCB Temescal GSA Wells with water qualtiy data may be added or removed over time Interconnected Surface Water and GDEs
Groundwater Depth to Water Depth to water, feet Multiple monitored wells outside the Basin, three new wells will be installed in
the future
Annual City of Corona Temescal GSA Groundwater in the Prado Management Area is shallow enough to support riprarian vegetation. Water levels in wells within the Prado area will be used.

T:\Projects\Corona GSP 46414\Deliverables\GSP\7 Monitoring\Table 7-1 Temescal Monitoring Program Summary.xlsx Todd Groundwater Des by: AR
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Temescal Basin GSP 7-3

7.1.1. Chronic Lowering of Groundwater Levels
As described in Plan Area Section 2, there are wells in the Basin with elevation data that are monitored by the City of Corona (Corona) and other agencies. The wells in the groundwater level monitoring program are shown on Figure 7-1 and listed in Table 7-2. The distribution of existing monitoring wells is uneven, with most monitoring wells clustered in the Channel Aquifer. All of the wells in the GSP monitoring network listed in Table 7-2 will continue to be monitored by the GSA.

Data for GSP implementation collected by Corona, with support from the other GSA members, will be compiled into the DMS developed as part of the GSP. Benefits of these efforts will accrue over the next few years and will support review and update of the monitoring program in the 2027 GSP evaluation and update.

7.1.1.1. Spatial and Vertical Coverage
Well density has been a consideration in identifying new dedicated monitoring well sites and adding existing wells to the monitoring program. California Department of Water Resources (DWR) guidance (DWR 2016d) generally recommends a monitoring well density of 4 wells per 100 mi2
, which would equate to 1.48 wells for the 37 mi2 Basin. The Temescal Basin monitoring program is consistent with this guidance. Many of the active wells are clustered in the Channel Aquifer, the principal aquifer. This is appropriate because most of the pumping for beneficial uses occurs in the Channel Aquifer and monitoring is needed to assess the sustainability management criteria.

Data on vertical groundwater gradients generally are lacking, as discussed in the Hydrogeologic Conceptual Model, Chapter 3. Vertical gradients also have not been distinguished because most monitoring data is from public supply wells, which generally have long screen zones and have not been designed to assess or monitor vertical gradients either locally or Basin-wide.

7.1.1.2. Monitoring Frequency
SGMA and the California Statewide Groundwater Elevation Monitoring (CASGEM) program require collection of static groundwater elevation measurements at least two times per year to represent seasonal low and seasonal high groundwater conditions (DWR 2010). Currently, the water level wells in the monitoring network are monitored at least quarterly, and most are monitored either monthly or continuously.

7.1.2. Reduction of Groundwater in Storage
As described in GSP Section 6.3, groundwater level Minimum Thresholds (MTs) are used as a proxy metric for groundwater in storage. Accordingly, the monitoring of groundwater levels described above in Section 7.1.1 also pertains to tracking sustainability for groundwater in storage.

In addition, GSP Regulations require annual evaluation and reporting of change in groundwater in storage.

Table 7-2. Wells in the Temescal Groundwater Sustainability Agency Monitoring Network Local Well Name State Well Number
X Coordinate (feet State
Plane CA Zone 6, NAD 83)
Y Coordinate (feet State
Plane CA Zone 6, NAD 83)
Production or
Monitoring Well
Water Level
Monitoring Well
(Yes/No)
Water Level Key Well
(Yes/No)
Water Quality
Monitoring Well
(Yes/No)
Corona 1 005S006W03Q001 6185537.873 2221306.937 Production Yes No No Corona 2 005S006W03J004 6185467.308 2222915.663 Production Yes No No Corona 3 005S006W03K001 6184752.886 2222980.793 Production Yes No Yes Corona 4 004S006W16C001 6178772.45 2246463.254 Production Yes No No Corona 6 003S006W31D002 6164825.949 2263859.333 Monitoring Yes No No Corona 7 003S006W31D001 6164856.185 2263922.413 Production Yes No Yes Corona 7A 003S006W30N003 6164825.605 2263909.491 Production Yes Yes Yes Corona 8 003S007W25J001 6163919.615 2265638.126 Monitoring Yes Yes Yes Corona 8A 003S007W25J002 6163885.958 2265713.322 Production Yes Yes Yes Corona 9 003S007W25M002 6159626.551 2265408.669 Production Yes No No Corona 9A 003S007W25M003 6159626.551 2265408.669 Production Yes Yes Yes Corona 11 003S007W27G001 6151398.941 2267565.162 Monitoring Yes Yes Yes Corona 11A Unavailable 6151465.535 2267567.377 Production Yes Yes Yes Corona 12 003S007W27F008 6150390.638 2266941.266 Production Yes No No Corona 12A 003S007W27F002 6150373.592 2266916.031 Production Yes Yes Yes Corona 13 003S006W31K001 6167356.423 2260664.289 Production Yes Yes Yes Corona 14 003S007W35C001 6155892.961 2263969.337 Production Yes Yes Yes Corona 15 003S007W26G001 6157114.482 2267464.919 Production Yes Yes Yes Corona 16 003S007W27A001 6151422.875 2267564.036 Monitoring Yes Yes Yes Corona 17 003S006W30N002 6165945.52 2265005.116 Monitoring Yes No Yes Corona 17A 003S006W25J003 6165945.52 2265005.116 Production Yes Yes Yes Corona 18 003S007W30F001 6134626.863 2268406.393 Production Yes No No Corona 19 003S007W25L001 6160509.304 2266247.265 Production Yes Yes Yes Corona 20 005S006W11D001 6187461.58 2220776.802 Production Yes No Yes Corona 21 005S006W03J005 6185101.792 2224409.774 Production Yes No Yes Corona 22 003S007W26J003 6157958.891 2265844.063 Production Yes Yes Yes Corona 23 003S007W25L002 6160785.538 2265696.4 Production Yes No Yes Corona 24 003S007W25K002 6161759.128 2266231.81 Production Yes No Yes Corona 25 003S007W25E002 6159434.755 2265962.111 Production Yes Yes Yes Corona 26 003S007W25C003 6160385.783 2268810.243 Production Yes Yes Yes Corona 27 003S007W01A001 6152402.182 2256818.413 Production Yes Yes Yes Corona 28 003S007W26K 6158978.97 2267786.881 Production Yes Yes Yes Corona 29 003S007W26A001 6159105.364 2268178.328 Production Yes Yes Yes Corona 30 Unavailable 6159542.311 2269428.52 Monitoring Yes Yes No Corona 31 003S007W26J004 6159001.737 2266396.339 Production Yes Yes Yes Corona 33 Unavailable 6175732.137 2265615.765 Production Yes Yes No Corona 10th/Lincoln 003S007W35B001 6156682.367 2263845.603 Monitoring Yes Yes No T:\Projects\Corona GSP 46414\Deliverables\GSP\7 Monitoring\Table 7-2 Wells in the Temescal Network.xlsx - Table 7-2 Todd Groundwater Des by: MR
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Temescal Basin GSP 7-5
For the GSP, the numerical groundwater model has been used to quantify the water budget and change in storage (see Water Budget, Chapter 5) using available information from the Monitoring Well Network. The numerical model (described in GSP Appendix J) fulfills data and reporting standards described in SGMA Section 352.4.

As described in Plan Area Section 2.4 and summarized in Table 7-1, the Temescal GSA monitoring program provides information needed to update the water budget and assess annual change in groundwater storage. This program compiles and reviews information on climate (rainfall and evapotranspiration), stream flow, imported water deliveries, wastewater percolation and water recycling, and groundwater pumping (municipal, industrial, and other). Groundwater in storage will be assessed annually using the numerical model, which will be recalibrated during each five-year GSP update.

7.1.2.1. Spatial Coverage
Evaluation of change in groundwater in storage involves several of the monitored variables listed in Table 7-1; monitoring locations are described in the table. Table 7-1 indicates locations of climate stations and stream gage locations.

7.1.2.2. Surface Water Monitoring
Temescal Wash is the main drainage in the Basin, originating at Lake Elsinore, 17 miles upstream of Basin. It passes from south to north through the Bedford-Coldwater Subbasin and then through the Basin before discharging into the Prado Management Area. There are two stream gages on Temescal Wash, one below Lee Lake at the upstream end of the Bedford-Coldwater Subbasin (Temescal Wash at Corona Lake; USGS 11071900) and one at Main Street downstream of the water reclamation facility in Corona (Temescal Creek above Main Street at Corona; USGS 11072100). These stream gages are operated and maintained by the United States Geological Survey (USGS 2020a).

7.1.2.3. Monitoring Frequency
Table 7-1 describes the data interval for the monitored variables that contribute to evaluation of groundwater in storage. Groundwater in storage will be assessed annually using the numerical model, which will be recalibrated during each five-year GSP update.

7.1.3. Seawater Intrusion
There is no monitoring for seawater intrusion and no gaging of tidal influence. The Basin is located over 20 miles inland from the Pacific Ocean, and its lowest elevations are around 1,000 feet above sea level. No risk of seawater intrusion exists in the Basin given its location and therefore no monitoring is needed.

7.1.4. Subsidence
The monitoring program will review Interferometric Synthetic Aperture Radar (InSAR) satellite-based data to identify and evaluate land subsidence in the Basin (see Table 7-1).

These data will be used to monitor rate and extent of ground surface elevation change as applicable and with reference to the MT and Measurable Objective (MO), which are described in Sustainability Criteria Section 6.5. These data represent measurements of

Temescal Basin GSP 7-6
ground surface displacement and thus are directly applicable to scientific assessment of potential subsidence.

7.1.4.1. Spatial Coverage
The InSAR data provide adequate coverage of the Temescal Basin. As described in Groundwater Conditions Section 4.3 and Sustainability Criteria Section 6.5. InSAR data are available for the entire Basin (and beyond), as shown with recent InSAR information from DWR on Figure 4-13. InSAR data will be cross-checked, and in conjunction with local groundwater level and pumping data, will be used to assess relationships between levels, pumping, and subsidence data.

7.1.4.2. Monitoring Frequency
Assuming continued data availability, the monitoring program will involve annual download of InSAR data with analysis for any signs (rate and extent) of cumulative inelastic subsidence. To date there have been no reports or other indications of subsidence in the Basin. While data will be reviewed annually, at this time detailed analysis relative to the Minimum Threshold and Measurable Objective is planned as part of the five-year GSP update. The reporting will be consistent with GSP Regulations.

7.1.5. Degraded Water Quality
In addition to the general monitoring objectives listed above, specific objectives for the GSP water quality monitoring program include the following:
• Collect groundwater quality data from the principal aquifer to identify and track trends of any water quality degradation,
• Map the movement of degraded water quality,
• Define the three-dimensional extent of any existing degraded water quality impact, • Assess groundwater quality impacts to beneficial uses and users, and • Evaluate whether management activities are contributing to water quality degradation.

Figure 7-2 shows the location of the existing wells that are sampled for water quality. The existing water quality monitoring programs for the Basin are described in Plan Area Section

2.4 Groundwater Conditions Section 4, and Sustainability Criteria Section 6.6. To summarize, the Temescal Basin monitoring program relies on annual or semi-annual measurements from Corona wells, the Santa Ana Regional Water Quality Control Board (RWQCB), and State Water Resources Control Board Division of Drinking Water (SWRCB-DDW). Corona currently monitors wells periodically for general minerals, physical parameters, and selected constituents of concern. These wells are shown on Figure 7-2 and listed in Table 7-2. As described in Groundwater Conditions Section 4 and discussed in depth in Section 6.6, a broad suite of inorganic constituents is sampled and analyzed and known regulated contamination sites are tracked. Total dissolved solids (TDS) and nitrate have been identified as the key constituents of concern for which sustainability criteria have been defined.

Temescal Basin GSP 7-7

7.1.5.1. Spatial and Vertical Coverage
The current monitoring network in the Basin is focused in the Channel Aquifer and is limited in other areas of the Basin. Figure 7-2 shows the spatial distribution of wells currently monitored. As with the groundwater level monitoring program, existing wells monitored by the GSA for groundwater quality will be evaluated relative to SGMA Section 352.4 requirements for well information. Also similar to the groundwater level monitoring program, the focus of monitoring is the Channel Aquifer as this is the primary source for municipal drinking water, a critical beneficial use of the Basin.

Vertical coverage is discussed in Groundwater Conditions Section 4.8, which indicates that the water quality monitoring programs in the Basin do not reveal vertical differences in water quality. Otherwise, vertical differences in water quality are uncertain; this reflects the fact that most monitored wells are pumping wells with long screens.

As stated in Section 6.6, the GSA will continue to improve and expanded the monitoring program to address spatial and vertical coverage.

7.1.6. Depletion of Interconnected Surface Water
The minimum threshold defined for depletion of interconnected surface water is defined by groundwater levels monitored near the Prado Management Area. At this time, wells in the groundwater level monitoring program are production wells with relatively deep screens that have not been sited and designed for tracking surface water-groundwater interactions.

The lack of shallow monitoring wells has been identified as a data gap.

Improvement of the surface water-groundwater monitoring program includes addition of three dedicated shallow monitoring wells, implemented as part of the projects and management actions outlined in this GSP.

Benefits of the new wells will accrue over the next few years and support characterization of the spatial and temporal exchanges between surface water and groundwater, plus identification of thresholds for undesirable results relating to riparian vegetation, which will be evaluated as part of the 2027 GSP evaluation and update.

7.1.6.1. Spatial and Vertical Coverage
As noted above, the existing monitoring network does not provide adequate coverage for monitoring interconnected surface water. New shallow monitoring wells will be installed to fill this data gap, as described in Chapter 8.

7.1.6.2. Temporal Coverage and Monitoring Frequency
Groundwater level monitoring in the new shallow monitoring wells will be implemented as part of the overall groundwater level monitoring program as described in Section 7.1.1.

Once sited and installed, the periods of record for new dedicated shallow wells will be established. Groundwater level data will be reviewed annually (for each annual report).

Detailed analyses of the relationships among deep and shallow groundwater level data, stream flow, and riparian conditions will be provided in the 2027 GSP evaluation and update (or sooner if extreme drought conditions and riparian mortality occur; see GSP Section 6.7).

Temescal Basin GSP 7-8

7.2. PROTOCOLS FOR DATA COLLECTION AND MONITORING
This section focuses on groundwater level monitoring (including regional and surface wateroriented) and groundwater quality sampling by the GSA. Other data (e.g., climate, streamflow, municipal pumping, subsidence) are compiled by other agencies.

This section describes general procedures for documenting wells in the monitoring program and for collecting consistent high-quality groundwater elevation and groundwater quality data. In general, the methods for establishing location coordinates (and reference point elevations for elevation monitoring) follow the data and reporting standards described in the GSP Regulations (Section 352.4) and the guidelines presented in USGS Groundwater Technical Procedures (Cunningham and Schalk 2011 and USGS 2021). These procedures are summarized below.

7.2.1. Field Methods for Monitoring Well Data
Background data for each monitoring well is required for its inclusion in the monitoring program. These data are generally available for wells in the network described in Table 7-2 and shown on Figures 7-1. As part of GSP implementation, location and elevation data will be acquired where missing, revised if conditions at a monitored well change, and added when new wells are brought into the program. The methods for acquiring these data follow:
• Location coordinates will be surveyed with a survey grade global positioning system (GPS) device. The coordinates will be in Latitude/Longitude decimal degrees and reference the North American Datum of 1983 (NAD83).
• Reference point elevations will also be surveyed with a survey grade GPS with elevation accuracy of approximately 0.5 feet.
o During surveying, the elevations of the reference point and ground surface near the well will be measured to the nearest 0.5 foot. o All elevation measurements will reference North American Vertical Datum of 1988 (NAVD88).

7.2.2. Field Methods for Groundwater Elevation Monitoring Reference points and ground surface elevations will be documented as described above prior to groundwater elevation monitoring in the field. Field methods for collection of depth-to-water measurements are described below:

1. Measurements in all wells will be collected within a three-day window whenever possible.

2. Active production wells should be turned off prior to collecting a depth to water measurement.

3. The standard period of time that a well needs to be off before a static measurement is taken is 48 hours.

4. To verify that the wells are ready for measurement, agency staff (from Corona, the City of Norco [Norco], and Home Gardens County Water District [HGCWD]) will coordinate with well operators and/or owners as necessary.

Temescal Basin GSP 7-9

5. Coordination with well operators/owners should occur approximately four days prior to the expected measurement date.

6. Depth to groundwater measurements collected by either electric sounding tape (Solinst or Powers type sounders) or by steel tape methods. Depth-to-water measurement methods are described in DWR’s Groundwater Elevation Monitoring Guidelines (DWR 2010). Depth to groundwater will be measured and reported in feet to at least 0.1 foot.

7.2.3. Field Methods for Groundwater Quality Monitoring Groundwater sampling is conducted by trained professionals from the GSA. Sampling follows standard monitoring well sampling guidelines such as those presented in the National Field Manual for the Collection of Water‐Quality Data (USGS 2021).

Generally, the wells have been pumped prior to sample collection, or are purged. Purging is conducted until field instruments indicate that water quality parameters (pH, oxidationreduction potential (ORP), specific conductance, and temperature) have stabilized and turbidity measurements are below five Nephelometric Turbidity Unit (NTUs). The pumping or purging demonstrate that the sample collected is representative of formation water and not stagnant water in the well casing or well filter pack. For groundwater, field temperature and conductivity are recorded while the well is being purged to ensure that physical parameters have stabilized before collecting a sample.

All groundwater samples are collected in laboratory‐supplied, pre‐labeled containers and include prescribed preservatives.

All field measurements are recorded in a field logbook or worksheets and the sample containers are labeled correctly and recorded on the chain‐of‐custody form. The applicable chain‐of‐custody sections are completed and forwarded with the samples to the laboratory.

Upon receipt of the samples at the laboratory, laboratory personnel complete the chain‐ofcustody.

Quality assurance and quality control (QA/QC) assessment of field sampling includes use of field blanks. Field blanks identify sample contamination that is associated with the field environment and sample handling. These samples are prepared in the field by filling the appropriate sample containers with the distilled water used for cleaning and decontamination of all field equipment. One field blank per sampling event is collected.

Samples are sent to a State‐certified laboratory that has a documented analytical QA/QC program including procedures to reduce variability and errors, identify and correct measurement problems, and provide a statistical measure of data quality. The laboratory conducts all QA/QC procedures in accordance with its QA/QC program. All QA/QC data are reported in the laboratory analytical report, including: the method, equipment, and analytical detection limits, the recovery rates, an explanation for any recovery rate that is less than 80 percent, the results of equipment and method blanks, the results of spiked and surrogate samples, the frequency of quality control analysis, and the name of the person(s) performing the analyses. Sample results are reported unadjusted for blank results or spike recovery.

Temescal Basin GSP 7-10

7.3. REPRESENTATIVE MONITORING
To allow quantification and tracking of sustainability criteria, representative monitoring sites, or wells, have been identified for 1) regional groundwater level monitoring and 2) monitoring shallow groundwater conditions where surface water-groundwater connection is likely and tied to groundwater dependent ecosystems (GDEs). These Key Wells are shown on Figure 7-1 and listed in Table 7-2. These have been designated by the GSA as the point at which sustainability indicators are monitored. Information on the quantitative values for minimum thresholds, measurable objectives, and interim milestones is included in Sustainability Criteria Section 6.

As discussed in Sustainability Criteria Section 6.3, change in groundwater in storage is closely related to groundwater levels, which can serve as a proxy for monitoring change in storage. Moreover, groundwater level MTs and MOs are sufficiently protective to ensure prevention of significant and unreasonable results relating to storage. Accordingly, continued monitoring of wells for groundwater levels also serve to track sustainability for storage.

As discussed in Section 6.5, the definition of undesirable results and the quantification of the MT and MO for subsidence are based on InSAR information on vertical displacement of the ground surface; these spatial and temporal data are publicly available from DWR.

Section 6.4 discusses seawater intrusion, which is not possible in this inland basin.

Section 6.6 describes undesirable results and defines sustainability criteria for water quality.

MTs and MOs are quantified in terms of the percentage of wells with concentrations exceeding the local and state goals for nitrate and TDS based on current conditions. The GSP water quality monitoring wells shown on Figure 7-2 and listed in Table 7-2 are sampled regularly to identify water quality problems and to track water quality trends.

7.4. DATA MANAGEMENT SYSTEM (DMS)
The GSA has been collecting and compiling groundwater data including water levels, water quality, and water use for the GSP. Before the creation of the GSA, the individual agencies of (Corona, Norco, and HGCWD) monitored water levels and water quality independently.

These data are compiled in relational databases, which consists of Access databases and ESRI geodatabases that have the capabilities for queries to quickly check and summarize data. As part of the GSP, the DMS has been modified to be practicable, usable, and intuitive for the purpose of GSP preparation and implementation. Appendix L details the final DMS.

The databases include easy to update tables and other datasets that assist in comparison of real time conditions and sustainability goals.

7.5. ASSESSMENT AND IMPROVEMENT OF MONITORING NETWORK
The GSA has actively engaged in assessment and improvement of its monitoring network.

This process has been intensified as part of the GSP, given the need to identify data gaps and to assess uncertainty in setting and tracking sustainability criteria. Monitoring

Temescal Basin GSP 7-11
improvements are a major part of GSP implementation and will be reviewed and updated for each five-year GSP evaluation.

7.5.1. Identification and Description of Data Gaps
Data gaps are identified in Table 7-3 according to major monitored variable and described in terms of insufficient number of monitoring sites and utilization of monitoring sites that are unreliable (including those that do not satisfy minimum standards). Data gaps also are described in terms of the location and reason for data gaps in the monitoring network, and local issues and circumstances that limit or prevent monitoring. Data gaps listed in Table 7-3 do not include gaps in understanding, which build on the monitoring network but also require investigation and analysis. These planned studies are described as Management Actions in GSP Chapter 8.

Table 7-3. Identification and Description of Data Gaps
Monitored
Variable
Insufficient
Sites Local Issues
Regional
groundwater
levels
No The water level network has historically relied largely on production wells.

Stream flow No There are gages on the major streams in the Basin.

Groundwater
extraction
No Most pumping is reported, there may be unreported
pumping but it is assumed to be de minimis.

Groundwater
quality
No Water quality sampling in the Basin is typically tied to regulatory requirements, the GSA will perform regular
monitoring of the well network and collect water quality data from all available sources.

Shallow
groundwater
levels
Yes No shallow dedicated groundwater monitoring wells are currently in the Basin. Long well screens in monitoring wells limit vertical groundwater quality characterization.

New shallow monitoring wells are included as a project
in Chapter 8.

7.5.2. Description of Steps to Fill Data Gaps
Monitoring data gaps have been identified for surface water and shallow groundwater level measurements.

Additional shallow groundwater level monitoring is required to better monitor interconnected surface water and GDEs in the Basin. Corona will locate and install three new shallow water level monitoring wells/piezometers adjacent to Prado Management Area, as described in Chapter 8, Projects and Management Actions.

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Temescal Basin GSP 8-1

PROJECTS AND MANAGEMENT ACTIONS
This chapter of the Groundwater Sustainability Plan (GSP) includes projects and management actions aimed at achieving sustainability goals and responding to changing conditions in the Temescal Subbasin (Basin). The projects and management actions are divided into three groups:
• Group 1 - Existing or established projects and management actions • Group 2 - Projects and management actions that have been or are under development
• Group 3 - Conceptual projects and management actions that can be considered in the future if any Group 2 projects fail to be implemented or additional intervention is required to achieve basin sustainability goals.

A summary of the projects and management actions in each of the groups is presented in Table 8-1. Additional discussion of each project is included in the sections that follow.

Table 8 1. Summary of Projects and Management Actions
Description Agency Category Status Anticipated Timeframe Groundwater Treatment City of Corona Project Ongoing Implemented WRF Percolation Ponds City of Corona Project Ongoing Implemented Water Level QA/QC City of Corona Project Ongoing Implemented Water Shortage Contingency Plans Cities of Corona and Norco Management Action Ongoing Implemented Water Conservation Programs Cities of Corona and Norco Management Action Ongoing Implemented Western Municipal Water District -
IRWMP
10 local cities/agencies including the GSA Management Action Ongoing Implemented Western Riverside County Regional
Wastewater Authority (WRCRWA)
GSA, Jurupa Community Services District,
and WMWD
Project Ongoing coordination Pending coordination with WRCRWA and partner agencies
Santa Ana Watershed Involvement GSA, Santa Ana Watershed Project Authority (SAWPA), and Santa Ana River
Dischargers Association (SARDA)
members
Management Action Ongoing Implemented
Interconnected Surface Water Monitoring
Wells Implementation
GSA Project In planning Well implementation within the first year of GSP adoption
Potable Reuse Feasibility Study GSA Project Not started Study initiation within the second year of GSP adoption
Mountain Runoff Capture Investigation GSA and RCFCWCD Project Not started Study initiation within five years of GSP adoption
Future Groundwater Treatment GSA Project Not started No current anticipated timeline Stormwater Capture, Treatment and
Recharge
GSA Project Not started No current anticipated timeline Santa Ana River Wastewater Discharge
Coordination for Shallow Groundwater
Conditions
GSA, SAWPA, and SARDA members Management Action Not started No current anticipated timeline Group 1 - Existing or established projects and management actions Group 2 – Projects and management actions have been developed or are under development Group 3 – Conceptual future projects and management actions T:\Projects\Corona GSP 46414\Deliverables\GSP\8 Projects and Management Actions\Table 8-1 Summary of Projects and Management Actions 20210623.xlsx - Sheet1 Carollo Engineers Des by: MR
Ckd by: EG

Temescal Basin GSP 8-3

8.1. GROUP 1 PROJECTS
Group 1 projects and management actions are considered existing or established commitments by the City of Corona (Corona), other agencies within the Temescal Groundwater Sustainability Agency (GSA), and/or affiliated agencies. Group 1 projects are either already in operation or are currently being implemented with anticipated near-term operation.

8.1.1. Groundwater Treatment
Corona relies on groundwater from the Temescal and Bedford-Coldwater Basins for up to 50 percent of its potable water supply. Table 8-2 shows Corona’s current and projected annual groundwater extraction volumes from these basins. As shown in the table, the Temescal Basin is responsible for most of Corona’s current and future groundwater supply.

Table 8-2. Existing and Projected Corona Groundwater Extraction Volumes (AFY) Basin 2020 2025 2030 2035 2040 2045
BedfordColdwater0 2,112 2,112 2,112 2,112 2,112
Temescal 16,239 13,000 13,000 13,000 13,000 13,000
Data Source: 2020 Urban Water Management Plan (Michael Baker 2021) Approximately half of the groundwater pumped in Corona is treated at the Temescal Desalter Facility, a city-owned, reverse osmosis (RO) facility. This facility reduces nitrates, per- and polyfluoroalkyl substances (PFAS), 1,2,3-Trichloropropane (TCP), perchlorates, and total suspended and dissolved solids (TSS and TDS) from water pumped from the Temescal Basin. In addition, ammonium hydroxide and sodium hypochlorite is added to the treated groundwater to act as a disinfectant and mitigate the formation of disinfection byproducts (DBPs) (Michael Baker 2021). The Temescal Desalter produces 10 million gallons per day (mgd) on average.

Corona maintains five continuously monitored blending facilities that blend the treated groundwater with both surface water and non-Desalter treated, locally produced groundwater. A portion of the groundwater utilized at the blend station that has not been treated by the Desalter is treated with sodium hypochlorite and ammonium hydroxide. This blend reduces the elevated amounts of fluoride, nitrate, and perchlorates found in the groundwater to a safe, consumable level.

The City of Norco (Norco) and Home Gardens County Water District (HGCWD) have service areas that overlie the Basin. The two entities do not currently pump groundwater from the Basin; however, should they utilize it for future supply they would likely require implementation of similar treatment.

Temescal Basin GSP 8-4

8.1.2. Water Reclamation Facility (WRF) Percolation Ponds Wastewater is treated at three Corona-owned and operated Water Reclamation Facilities (WRF-1, WRF-2 and WRF-3). The average annual production of treated wastewater (effluent) from these sources is approximately 11.35 mgd, or 12,700 acre-feet per year (AFY). Supply is anticipated to increase incrementally due to population growth by an additional 0.88 mgd through 2040 (about 7.8 percent).

WRF effluent is allocated to three end uses: 1) discharge to the Santa Ana River Watershed (SWRCB 2021), 2) reuse via the reclaimed water distribution system, and 3) discharge to offsite percolation ponds. WRF-1 and WRF-2 both contribute effluent to all of these end uses while WRF-3 only contributes effluent to the reclaimed water system. The three offsite percolation ponds overlie the Basin and allow for recharge. One of the ponds is located along Lincoln Avenue and the other two at the end of Rincon Street near Cota Street. Table 8-3 shows the total annual effluent sent to the percolation ponds in the last five years.

Table 8-3. WRF Annual Percolation Pond Contributions (AFY) Facility 2016 2017 2018 2019 2020
WRF-1 1,364 5,273 4,493 5,026 4,987
WRF-2 734 1,207 1,306 1,462 1,774
Data Source: 2020 Urban Water Management Plan (Michael Baker 2021)

8.1.3. Water Level Quality Assurance and Quality Control (QA/QC) Corona is conducting water level quality assurance and quality control (QA/QC) activities to maintain and increase the integrity and reliability of ongoing groundwater elevation data collection. Static and pumping water level depths are collected, by Corona water operators, once a month from each groundwater well location identified in Chapter 7, Monitoring Network.

The current QA/QC process practiced by Corona involves the following activities:
• The data is entered into Corona’s database at the end of the water operator’s shift. • The data is also written on a whiteboard in the Drinking Water staff crew room.

Corona is updating their QA/QC policies to ensure manual entry errors are minimized by creating “Alert” pop up boxes in their database.
• The minimum, maximum, average, and standard deviation static and pumping water level depths are calculated for each monitored well.
• The “Alert” pop up will appear if the data entered is greater than the upper limit or less than the lower limit for any monitoring event.
o The upper limit for each well will be the standard deviation times two plus the average.
o The lower limit will be the average minus two times the standard deviation.

Temescal Basin GSP 8-5
• The Alert pop up still allows the operator to enter the data but makes them aware that the data being entered is outside the range of the historical measurements. • It will be up to the water operator to recheck the data being entered, and either confirm or correct the measurement.
• A report including the most recent static and pumping water levels for each monitored well will be created once a month, and this report will be reviewed by operators and management to identify data collection errors and/or trends in water levels.

8.1.4. Water Shortage Contingency Plans
Corona’s 2020 Urban Water Management Plan (UWMP) estimated the available supply from imported water, groundwater, and reclaimed water at a total of 50,000 AFY. Using this baseline supply, a water shortage contingency plan (WSCP) was developed. The WSCP has six shortage stages based on available supply and associated deficit. Each stage has associated response actions to ensure appropriate reductions in water use (Michael Baker 2021). Table 8-4 shows each of the stages and associated supply. Note that the Ordinance 2962 Water Conservation Stage column will be discussed further in Section 8.1.5. Detailed information on response actions for a given stage can be found in the 2020 UWMP and is discussed further in Section 8.1.5.

Table 8-4. WSCP Shortage Level Determination
WSCP
Stage
Ordinance 2962 Water
Conservation Stage Condition
Available
Supply (AFY)
Deficit
(AFY)
0 1 No Shortage 50,000 None
1 1 10 percent Shortage 45,000 None
2 1 20 percent Shortage 40,000 None
3 2 30 percent Shortage 35,000 5,000
4 3 40 percent Shortage 30,000 10,000
5 4 50 percent Shortage 25,000 15,000
6 5 > 50 percent Shortage < 25,000 > 15,000
Data Source: 2020 Urban Water Management Plan (Michael Baker 2021) Norco has developed their own respective WSCP based on the six stages and respective percent shortage condition as well (Norco 2021).

8.1.5. Water Conservation Program
In 2009, Corona implemented Ordinance No. 2962, amending the Corona Municipal Code to provide framework for water conservation and drought response measures. The Ordinance defines five stages of water conservation, corresponding water consumption objectives (10 percent to 40 percent or greater), and associated conservation and drought response

Temescal Basin GSP 8-6
measures. Table 8-4, above, shows the five stages and associated storage condition and available supply. The following is a summary of the shortage response actions to be taken at each water conservation stage (per Ordinance No. 2962), more detailed information can be found in the 2020 UWMP (Michael Baker 2021).
• Stage 1: No water shortage, or “normal water supply”, applies when Corona is able to fully meet all customer water demands. Normal water efficiency programs will be in effect during this time.
• Stage 2: Water customers shall reduce consumption by 10 to 15 percent. Examples of water reduction measures include irrigation limitations and residential car washing and drainage restrictions.
• Stage 3: Water customers shall reduce consumption by 16 to 20 percent. This includes all restrictions in Stages 1 and 2 and adds additional restrictions, such as limiting new construction water meters and prohibiting ornamental fountains or similar structures.
• Stage 4: Water customers shall reduce consumption by 21 to 40 percent. This includes all restrictions in Stages 1, 2, and 3 and adds additional restrictions, such as prohibiting the issuance of new construction water meters and prohibiting issuance of new building permits.
• Stage 5: Water customers shall reduce consumption by at least 41 percent. This includes all restrictions in Stages 1, 2, 3, and 4 and adds additional restrictions, such as prohibiting all outdoor watering, except for recycled water use for fruit tree irrigation.

Norco has developed their own respective conservation plan based more directly on the WSCP stages discussed in the prior section (Norco 2021).

8.1.6. Participation in Integrated Regional Water Management Plans (IRWMP) The Western Municipal Water District (WMWD) Integrated Regional Water Management Plan (IRWMP) was prepared in 2008 (KJ 2008). The purpose of the plan was to address long range water quantity, quality, and environmental planning needs within the WMWD service area. The IRWMP was prepared in cooperation with the ten cities/water districts receiving water from WMWD, including the cities of Corona and Norco. The creation of the IRWMP provided a coordinated water management strategy to make sure water resources are being used responsibly throughout the region.

More recently, in 2018, the Santa Ana River Watershed Project Authority (SAWPA) developed the One Water One Watershed (OWOW) Plan Update to serve as the IRWMP for the Santa Ana River Watershed (SAWPA 2018). The OWOW Plan was initially developed in 2010 and has been subsequently updated in 2014 and 2019. The OWOW Plan was prepared with engagement from over 4,000 stakeholders. Including 120 water agencies and 63 incorporated cities within the watershed. All three GSA members were involved in the planning process.

Temescal Basin GSP 8-7
The goals of the 2019 OWOW Plan are to achieve resilient water supply, improve water quality, preserve natural spaces, improve data integration and tracking, diminish environmental injustices, and educate visitors within the Santa Ana River Watershed.

8.1.7. Western Riverside County Regional Wastewater Authority (WRCRWA) The Western Riverside County Regional Wastewater Authority (WRCRWA) is a joint powers authority (JPA) consisting of the cities of Norco and Corona, Jurupa Community Services District, Home Gardens Sanitary District, and WMWD. The WRCRWA Plant has a 14 mgd capacity and will soon produce recycled water for local irrigation use.

As JPA partners, Corona and Norco will be entitled to up to 2 and 2.7 mgd respectively of recycled water allocated for use in their service areas, reducing local pumping from the Temescal Basin.

8.1.8. Santa Ana Watershed Involvement
SAWPA is a JPA formed to develop and maintain regional plans and projects that will protect the Santa Ana River Basin and associated water resources. Corona participates in the task forces and working groups within the watershed noted in Table 8-5.

Table 8-5. City of Corona Santa Ana Watershed Task Forces/Groups Name Brief Description
SAWPA – Emerging
Constituents Task Force
In 2007, a workgroup was formed among the water recharging agencies and publicly owned treatment works (POTWs) to
address a characterization program for emerging constituents.

SAWPA was requested to administer the development of a 2- phase approach.

SARDA – Santa Ana River
Discharge Agencies
Working group of Santa Ana River (SAR) discharge agencies jointly implementing the annual mercury monitoring in the SAR.

SAWPA – Basin
Monitoring Task Force
As an outgrowth of the Nitrogen/TDS Task Force, the agencies responsible for implementing the Basin Plan Amendments
formed the Basin Monitoring Task Force, and SAWPA was
identified to administer/facilitate that effort.

SAWPA – Imported
Water Recharge
Workgroup
The purpose of this Workgroup is to undertake tasks defined in a Cooperative Agreement among the water recharging agencies to assure that the water quality (Nitrogen and TDS) in
groundwater is protected. These tasks include regular reporting on the amount and quality of water recharged, the ambient water quality in each groundwater management zone, and 20- year groundwater flow and quality model projections for each groundwater management zone that is recharged. All reports are provided to the Regional Water Quality Control Board.

Temescal Basin GSP 8-8
In addition, Corona discharges treated wastewater from one of their three water reclamation plants (WRF-1) to Temescal Wash within the Santa Ana River Watershed.

Corona discharged an average of approximately 2,000 AFY to the watershed from WRF-1 (Michael Baker 2021). The discharged water serves a dual purpose of maintaining riparian habitat as well as recharging the Basin via percolation.

8.2. GROUP 2 PROJECTS
Group 2 projects will be implemented to meet Basin sustainability goals, in conjunction with Group 1 projects.

8.2.1. Shallow Monitoring Well Installation
A total of three shallow monitoring wells will be drilled in the Prado Management Area. The wells will be approximately 40 to 60 feet in depth and 2-inches in diameter. Figure 8-1 shows the proposed, approximate locations of these monitoring wells.

The approximate locations have been identified based on existing groundwater conditions, land access, and the ongoing construction of the new Prado Dike. Areas north of the Prado Dike will potentially be inundated in the future, and future monitoring wells need to be located outside the area of inundation. The locations shown on Figure 8-1 are above 545- feet mean sea level (msl) elevation. The existing spillway elevation of the Prado Dam is 543- feet msl, so these monitoring well locations should be above the future area of inundation.

8.2.1.1. Measurable Objective Expected to Benefit from Project or Management Action The project will allow for continuous monitoring at representative sites in the Prado Management Area. This will allow Corona to track groundwater levels in the southern part of the Management Area along with the rest of the Basin. Groundwater levels in these wells will be incorporated into the interconnected surface water sustainable management criteria in the 5-year GSP update. Once established, the sustainable management criteria for these wells will help guide future management actions required by upstream Santa Ana River Watershed partners.

8.2.1.2. Circumstances for Implementation
Corona has already initiated the planning process to install these monitoring wells. It is anticipated that these can be implemented with existing on-call contracts.

8.2.1.3. Public Noticing
The public will be notified per California Environmental Quality Act (CEQA)requirements.

8.2.1.4. Permitting and regulatory process
Wells will be drilled on private or City of Corona property. The project will comply with all CEQA, Riverside County, and discharge permitting requirements. Corona will coordinate with the Santa Ana Regional Water Quality Control Board (RWQCB) to plan for discharging any and all water in accordance with RWQCB general permits.

Temescal Basin GSP 8-9

8.2.1.5. Project Timetable
The monitoring wells will be installed within two years of GSP implementation.

8.2.1.6. Plan for Project Implementation
Three monitoring wells will be drilled in areas in the Prado Management Area. The wells will be approximately 40 to 60 feet deep and will be 2-inches in diameter with polyvinyl chloride (PVC) casings and screens, bentonite seals, and cement sanitary seals. The well drilling process will be completed with existing Corona on-call contracts.

8.2.1.7. Expected Benefits
The installation of three monitoring wells will allow Corona to track groundwater levels in the Prado Management Area and identify timing and triggers for future management actions, if needed.

8.2.1.8. Legal Authority
By California state law, water districts and land use jurisdictions have the authority to take action to ensure sufficient water supply is available for present or future beneficial use within their service areas.

8.2.1.9. Estimated Costs and Funding Plan
Costs are anticipated to be $40,000 to $50,000 in total for the installation of the three wells.

The project will be financed from existing Corona budgets.

8.2.1.10. Management of Project
The project will be managed by the City of Corona Department of Water and Power with support from other staff and outside technical experts, as necessary.

8.2.1.11. Relationship to Additional GSP Elements
The addition of three new monitoring wells in the Basin will identify future management actions required by upstream Santa Ana River Watershed partners. This is discussed in further detail in Group 3.

8.2.2. Potable Reuse Feasibility Study
As noted in the Group 1 project section, the WRCRWA facility is near-future reclaimed water supply source for Corona. Corona will conduct a potable reuse feasibility study to evaluate various potable reuse strategies and opportunities for optimizing use of reclaimed water supply in conjunction with existing reclaimed water supply from WRF-1, 2, and 3. This study would likely involve looking at specific end uses, water supply benefits, regulatory requirements, treatment requirements, infrastructure requirements, and associated costs.

8.2.2.1. Measurable Objective Expected to Benefit from Project or Management Action Corona is exploring future options to optimize use of recycled water in the Basin in order to reduce groundwater dependence.

Temescal Basin GSP 8-10

8.2.2.2. Circumstances for Implementation
Corona is currently exploring a wide range of options to increase their water supply portfolio.

8.2.2.3. Public Noticing
Public noticing is not required for this project. Should potable reuse projects be recommended for the region, Corona may choose to adopt a comprehensive outreach and education program to solicit public input.

8.2.2.4. Permitting and regulatory process
Permits are not required for this project. This study will evaluate potential potable reuse projects and will consider potential regulatory requirements for implementation.

8.2.2.5. Project Timetable
The study is anticipated to be one year in duration, initiating approximately two years after adoption of the GSP.

8.2.2.6. Plan for Project Implementation
Corona would need to develop a study scope, issue a project solicitation, and hire a technical consultant to perform the evaluation.

8.2.2.7. Expected Benefits
This study will evaluate and recommend future potable reuse projects to be implemented in the region.

8.2.2.8. Legal Authority
Legal authority is not required to perform a feasibility study.

8.2.2.9. Estimated Costs and Funding Plan
The study is anticipated to cost between $150,000 to $200,000 and will likely be funded through City of Corona sources. Grant funding is available through the State Water Resources Control Board (SWRCB) and the United States Bureau of Reclamation (USBR) should Corona choose to pursue alternate means of funding.

8.2.2.10. Management of Project
The project will be managed by the City of Corona Department of Water and Power with support from other staff and outside technical experts, as necessary.

8.2.2.11. Relationship to Additional GSP Elements
Because this project is a feasibility study, it is not anticipated to have any impact on other GSP projects or management actions described in this chapter. Future potable reuse projects recommended as a result of this study will reduce groundwater dependence in the region.

Temescal Basin GSP 8-11

8.2.3. Mountain Runoff Capture Feasibility Study
Riverside County Flood Control and Water Conservation District (RCFCWCD) operates major flood control facilities such as dams, flood basins, levees, open channels, and major (36-inch or larger) underground storm drains in a 2,700 square mile service area in the western portion of Riverside County. Rainwater runoff from the Santa Ana Mountains flows into RCFCWCD flood basins during storm events to mitigate downstream flood damage. A Mountain Runoff Capture Feasibility Study would explore options for operational changes that would provide the dual benefit of flood control and groundwater recharge.

8.2.3.1. Measurable Objective Expected to Benefit from Project or Management Action Although this study would yield no direct measurable objectives, future recommended projects would help to raise groundwater levels in the Basin and reduce the threat of land subsidence.

8.2.3.2. Circumstances for Implementation
Corona is currently exploring options to increase groundwater recharge. An initial study would be conducted to establish a basis for inter-agency coordination between RCFCWCD and Corona on the subsequent feasibility study.

8.2.3.3. Public Noticing
Public noticing is not required for this project. Should implementation projects be recommended for the region, Corona may choose to adopt a comprehensive outreach and education program to solicit public input.

8.2.3.4. Permitting and regulatory process
Permits are not required for this project. This study will evaluate potential runoff capture projects and will consider potential regulatory requirements for implementation.

8.2.3.5. Project Timetable
The initial study would be undertaken within the first five years of GSP adoption and be approximately three months in duration. After appropriate inter-agency coordination, the subsequent feasibility study is anticipated to be approximately six months in duration.

8.2.3.6. Plan for Project Implementation
RCFCWCD owns and operates this infrastructure. Interagency discussion should be conducted during the initial study to coordinate on development of the feasibility study.

8.2.3.7. Expected Benefits
This study will evaluate and recommend operational changes to the RCFCWCD flood basins that would enable the system to be used for both flood control and groundwater recharge to the Basin.

8.2.3.8. Legal Authority
Legal authority is not required to perform a feasibility study.

Temescal Basin GSP 8-12

8.2.3.9. Estimated Costs and Funding Plan
The study is anticipated to cost approximately $75,000. Corona could explore potential funding sources through the California Department of Water Resources (DWR).

8.2.3.10. Management of Project
The project will be managed by the City of Corona Department of Water and Power with support from other staff and outside technical experts, as necessary.

8.2.3.11. Relationship to Additional GSP Elements
Because this project is a feasibility study, it is not anticipated to have any impact on other GSP projects or management actions described in this chapter. Future projects implemented as a result of this study will reduce groundwater dependence in the region.

8.3. GROUP 3 PROJECTS
Group 3 projects are conceptual activities that can be considered in the future if any Group 2 projects fail to be implemented or additional intervention is required to achieve basin sustainability goals. These projects are not planned for near-term implementation and have been developed to a lesser degree than Group 2 projects but will be evaluated further, as needed, should a given Group 3 project be deemed critical for Basin sustainability.

8.3.1. Groundwater Treatment
A study conducted in 2016 focused on the detection of PFAS in Corona wells as well as potential treatment options (Carollo 2017). Subsequently, Corona initiated an ongoing PFAS study likely to be complete in mid to late 2021.

Corona has future interests in advanced groundwater treatment to treat for previously detected PFAS as well as addressing TDS, nitrate, and TCP. Groundwater treated to remove these contaminants could potentially be recharged back into the Basin, improving water quality.

8.3.2. Stormwater Capture, Treatment, and Recharge
Harvesting of urban stormwater has a potential benefit of reducing the loss of water from the Basin. There are a number of different approaches to stormwater capture and use including:
• Onsite rain barrels to promote reuse and reduce generation of urban runoff • Larger scale capture in stormwater vaults/cisterns and reuse • Capture and infiltration approaches including infiltration basins, bioretention, and permeable pavement
• Dry wells for capture and recharge
• Diversion to WRFs for treatment and reuse.

Corona has conducted a preliminary investigation on capture of stormwater from a lined channel on Oak Avenue and transfer to the existing percolation ponds (Todd 2011).

Temescal Basin GSP 8-13
It is anticipated that a future study would explore potential sources of urban runoff, estimated yield, mechanisms for augmenting or offsetting water supplies, treatment needs, capital costs, and operation and maintenance (O&M) costs. An initial investigation would establish the basis for further exploration of the feasibility of specific stormwater capture approaches and projects.

8.3.3. Santa Ana River Wastewater Discharge Coordination for Shallow Groundwater Conditions
This project would be implemented contingent on the outcome of the Prado Management Area monitoring well installation, a previously discussed Group 2 project. The Prado Management Area is currently maintained by wastewater discharge from upstream parties.

If monitoring well data indicates that groundwater elevations are falling, it is likely due to reduction of wastewater discharge flow.

The project approach would be two-fold and encompass the following:

1. Evaluation and examination of current wastewater discharges into the Prado Management Area from contributing parties including SAWPA member agencies (Eastern Municipal Water District, Inland Empire Utilities Agency, Orange County Water District, San Bernardino Valley Municipal Water District, and Western Municipal Water District).

2. Coordinate with partners to identify solutions to falling groundwater water levels in the Prado Management Area.

Path: T:\Projects\Corona GSP 46414\GIS\Maps\Figures\GSP Figures\Chapter 8 - Projects and Managment Actions\Figure 8-1 Shallow Monitoring Well Locations.mxd Approximate 545 foot Ground Surface Elevation Contour
Recommended Shallow Monitoring Well General Search Area Figure 8-1
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Temescal Basin GSP 9-1

IMPLEMENTATION PLAN
While the Temescal Subbasin (Basin) is considered to be sustainably managed, this status is by no means taken for granted. Potential effects of growth and climate change have been evaluated by means of modeling simulations, but effects are likely to be cumulative, and thereby present challenges to sustainability. Accordingly, additional projects and actions must be continued or implemented to satisfy the Sustainability Goal to the foreseeable planning horizon. Implementation of the Groundwater Sustainability Plan (GSP) by the Temescal Groundwater Sustainability Agency (GSA) will begin following adoption of the plan by the GSA in 2022 and continue through 2042. The GSP will be implemented to sustainably manage groundwater in the Basin under the authority of the GSA and its member agencies the City of Corona (Corona), the City of Norco (Norco), and the Home Gardens County Water District (HGCWD) as provided by the Sustainable Groundwater Management Act (SGMA).

After submittal of the GSP to the California Department of Water Resources (DWR) and during the DWR review period, the GSA will begin implementing the projects and management actions described in Chapter 8 and will communicate with stakeholders throughout implementation.

9.1. PLAN IMPLEMENTATION RESOURCES AND RESPONSIBILITIES Resources to implement the GSP will be derived from funds and personnel from the GSA parties (Corona, Norco, and HGCWD) and qualified firms contracted to perform specific specialized services.

Personnel from the three GSA parties will be responsible for collection of information from their respective facilities or within their area of influence in the Basin. This will include depth to groundwater measurements, collection of groundwater quality samples, groundwater extractions, use of surface water supplies, and total water use. This information will be maintained by each GSA party for inclusion in annual reports, GSP updates, and storage in the Data Management System (DMS).

Annual GSP reporting, specialized activities included in projects and/or management actions, and periodic GSP updates will be contracted by the GSA to specific specialized firms with relevant experience and expertise. Individual parties within the GSA may be responsible for developing requests for proposals (RFPs), contracting, and managing these activities with contractors and/or consultants.

9.2. ANNUAL REPORTING
The GSA is required to submit annual reports to DWR by April 1st of each year following adoption of the GSP. The first annual report will be due April 1, 2022. Each annual report will include the following components for the preceding water year as described in GSP Regulations:
• General information – Executive summary, location map.

Temescal Basin GSP 9-2
• Detailed description and graphical representation of the following components of the Basin:
o Groundwater elevation data from monitoring wells within the monitoring network.
o Groundwater extraction data for the preceding water year. o Surface water supply used or available for use.
o Total water use.
o Change in groundwater storage.
• Description of progress towards implementing the GSP – implementation of projects or management actions since the previous annual report.

The first annual report will be prepared to include data and information from the end of the period included in this GSP (end of water year 2018) through to the end of water year 2021.

The costs associated with producing annual reports will be incorporated into the Corona annual budget.

9.3. NEW INFORMATION AND CHANGES
The GSP has been developed based on the best available information. However, it is recognized that during implementation of the GSP, new information on groundwater conditions, changes in land use or climate, and or changes in the regulatory environment can be expected. Changes in GSP administration may also be appropriate based on experience. When these changes occur, the GSA will react with appropriate changes in GSP administration, data collection, and/or groundwater management methods. If the changes are significant, stakeholders and the GSA will be kept informed of these changes via the Corona GSP website and emails to stakeholders.

9.4. PERIODIC EVALUATIONS
The GSA will evaluate the GSP at least every five years and provide an assessment to DWR as required by GSP Regulations. This will include an update on the progress of achieving sustainability goals in the Basin and assessment of the following:
• Current groundwater conditions for each sustainability indicator applicable to the Basin relative to measurable objectives and minimum thresholds. • The implementation of any projects or management actions and their effect on groundwater conditions.
• Revisions to the basin setting, management areas, or the identification of undesirable results and the setting of minimum thresholds and measurable objectives resulting from significant changes, new information, or changes in water use.
• The monitoring network within the Basin, including any data gaps and areas of the Basin that are represented by data that does not satisfy the requirements of SGMA requirements.
• Significant new information that has been made available since GSP adoption, amendment, or last assessment.

Temescal Basin GSP 9-3
• Relevant actions taken by the GSA, including a summary of regulations or ordinances related to the GSP.
• Any enforcement or legal actions taken by the GSA to continue the sustainability goals of the Basin.
• Completed or proposed GSP amendments.

The cost of the periodic updates is dependent on the complexity of changes occurring in the Basin since adoption of the GSP but are estimated to be $250,000 per update (2021 dollars).

9.5. PROJECTS AND MANAGEMENT ACTIONS
Projects and management actions are described in Chapter 8, each in terms of technical description, feasibility and implementation, benefits, costs and financing, and timeline. The Projects and Management Actions are listed below in the same order as presented in Chapter 8.

Group 1 - Existing or established projects and management actions • Groundwater Treatment
• Water Reclamation Facility (WRF) Percolation Ponds
• Water Level Quality Assurance and Quality Control (QA/QC) • Water Shortage Contingency Plans (WSCPs)
• Water Conservation Programs
• Western Municipal Water District Integrated Regional Water Management Plan (IRWMP)
• Western Riverside County Regional Wastewater Authority (WRCRWA) • Santa Ana Watershed Involvement
Group 2 – Projects and management actions that have been or are under development
• Interconnected Surface Water Monitoring Wells Implementation • Potable Reuse Feasibility Study
• Mountain Runoff Capture Investigation
Group 3 – Conceptual future projects and management actions • Future Groundwater Treatment
• Stormwater Capture, Treatment and Recharge
• Santa Ana River Wastewater Discharge Coordination for Shallow Groundwater Conditions
The projects and management actions described here work together toward the sustainability goal and objectives, namely: to provide a reliable and efficient groundwater supply, to provide reliable storage, to protect groundwater quality, to support beneficial uses of interconnected surface waters, and to support integrated and cooperative water resource management.

Temescal Basin GSP 9-4

9.6. SCHEDULE FOR IMPLEMENTATION
Table 9-1 is an estimated timeline for implementation. The timeline columns include the individual years 2021 through 2025, which are followed by five-year intervals to 2040 to 2045. With implementation officially starting in 2022, the last interval includes the 2042 deadline for the 20-year implementation to achieve the sustainability goal.

The projects and management actions, and GSP Administration, Monitoring, and Reporting are listed in rows and as warranted. As shown, most projects and management actions have been ongoing. Some will be initiated following GSP adoption and continued during implementation.

Table 9 1. Estimated Timeline for Projects and Management Actions GSP Implementation Period
2021 2022 2023 2024 2025 2026-2030 2031-2035 2036-2040 2041-2045 Group 1 - Existing or established projects and management actions Groundwater Treatment
WRF Percolation Ponds
Water Level QA/QC
Water Shortage Contingency Plans
Water Conservation Programs
Western Municipal Water District - IRWMP
Western Riverside County Regional Wastewater Authority (WRCRWA) Santa Ana Watershed Involvement
Group 2 – Projects and management actions that have been or are under development Interconnected Surface Water Monitoring Wells Implementation Potable Reuse Feasibility Study
Mountain Runoff Capture Investigation
Group 3 – Conceptual future projects and management actions Future Groundwater Treatment (to be determined)
Stormwater Capture, Treatment and Recharge (to be determined) Coordination with Upstream Santa Ana River Partners (to be determined) GSP Administration, Monitoring, and Reporting
GSP Administration
Ongoing Monitoring
Annual Reporting
Periodic GSP Evaluation and Updates
Description
T:\Projects\Corona GSP 46414\Deliverables\GSP\9 Implementation Plan\Table 9-1 Implementation Timeline.xlsx - Table 9-1 Todd Groundwater Des by: CT
Ckd by: MR

Temescal Basin GSP 9-6

9.7. GSP IMPLEMENTATION COSTS
Implementation costs include costs to continue monitoring as described in Chapter 7, implement management actions and projects as described in Chapter 8, and complete annual reports and periodic GSP evaluation and updates as required by SGMA. As summarized in Table 9-2, total annual costs (2021 dollars) are estimated at $100,000 per year for GSP administration and annual reporting. Costs for previously implemented existing ongoing Group 1 management actions and project and monitoring activities are not included in this total. Estimated single occurrence costs for activities anticipated to occur in the first 5 years of GSP implementation and the first periodic GSP evaluation and update total $515,000 to $575,000 (2021 dollars). Costs for conceptual future Group 3 projects and management actions are not included in this total.

Table 9-2. GSP Implementation Cost Estimates
Management Actions, Projects, and GSP Administration Estimated Costs GSP Administration and Annual Reporting $100,000/year
Total Estimated Annual Implementation Costs $100,000/year Interconnected Surface Water Monitoring Wells Implementation $40,000 to $50,000 Potable Reuse Feasibility Study $150,000 to $200,000
Mountain Runoff Capture Investigation $75,000
First Periodic Evaluation and GSP Update (2027) $250,000 Total Estimated One-Occurrence Costs (First 5 years) $515,000 to $575,000 Future Groundwater Treatment To be decided
Stormwater Capture, Treatment and Recharge To be decided Coordination with Upstream Santa Ana River Partners To be decided

9.7.1. Funding Methods
The funding method for operating expenses and GSP implementation costs is by contributions by GSA member agencies (Corona, Norco, and HGCWD). This is the same mechanism utilized to fund development of the GSP (with significant supplemental contribution though California Proposition 1 Grant funding). Corona will be responsible for most of the ongoing implementation costs, which are within budget projections for the next several years.

Sources of funding have and will continue to vary according to the project or management action (see Chapter 8). Funding for planning and implementation of some projects and management actions may be achieved with local, state, and federal sources. The local agencies track opportunities for outside financing (grants or loans) from state water programs and federal infrastructure funding. For local financing, the agencies update their financial plans and rates as needed.

Temescal Basin GSP 10-1

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Temescal Basin GSP 10-2
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California State Water Resources Control Board (SWRCB), 2012, Order Canceling Protest, Approving Change in Purpose of Use, Place of Use, and Discharge Quantity, City of Corona Wastewater Petition WW-56,August 15, available at:
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California State Water Resources Control Board (SWRCB), 2020c, White Paper Discussion On: Economic Feasibility Analysis In Consideration of a Hexavalent Chromium MCL, February,
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Temescal Basin GSP 10-3
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Temescal Basin GSP 10-4
ICF, Inc., 2020, Upper Santa Ana River habitat conservation plan, stakeholder draft, prepared for San Bernardino Valley Water District, San Bernardino, CA, available at:
http://www.uppersarhcp.com/Additional.aspx, last accessed December 2020.

Jurgens, B. C., Fram, M. S., Belitz, K., Burow, K. R., & Landon, M. K., 2010, Effects of groundwater development on uranium: Central Valley, California, USA. Groundwater, 48(6), 913-928, https://ca.water.usgs.gov/pubs/2010/JurgensEtAl2010.pdf.

Kennedy/Jenks Consultant (K/J), 2008, Western Municipal Water District Integrated Regional Water Management Plan 2008 Update, prepared for the Western Municipal Water District, May, https://www.wmwd.com/214/Integrated-Regional-Water-Management-Pla.

KWC Engineers, 2016, City of Corona 2015 Urban Water Management Plan, July, available at: https://www.coronaca.gov/home/showdocument?id=4318
Luhdorff and Scalmanini Consulting Engineers (LSCE), Borchers JW, Grabert VK, Carpenter M, Dalgish B, Cannon D, 2014, Land subsidence from groundwater use in California, report prepared by LSCE with support by the California Water Foundation, http://californiawaterfoundation.org/wp-content/uploads/PDF/1397858208- SUBSIDENCEFULLREPORT_FINAL.pdf, accessed July 2020.

McMichael, David, 2021, Temescal Creek Riparian Habitat Timeline, prepared for Orange County Water District, December, included in Appendix I.

Michael Baker International, 2021, City of Corona 2020 Urban Water Management Plan, Volume 1, Draft, June
https://www.coronaca.gov/home/showpublisheddocument/20172/637576204172900000.

Natural Resources Conservation Service (NRCS), 2020, SSURGO soil survey online map database available at: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx, last accessed July 2020.

PBS&J and Ron Barto, Ground Water Consultant, 2004, Surface Disposal Pilot Project for the City of Corona, July.

Riverside County Department of Environmental Health (RCDEH), 2020, Wells Services Website, available at https://www.rivcoeh.org/OurServices/Wells, last accessed July 2020.

Riverside County Planning Department, 2015, County of Riverside General Plan, December 8, available at: https://planning.rctlma.org/General-Plan-Zoning/GeneralPlan Riverside County Regional Conservation Authority (RCRCA), 2020, Western Riverside County multispecies habitat conservation plan, available at: https://www.wrc-rca.org/rcamaps/, last accessed July 2020.

Russell, Kerwin, 2020, Natural Resources Manager, Riverside-Corona Resource Conservation District, e-mails to Gus Yates, Todd Groundwater, August 1 and 3.

Temescal Basin GSP 10-5
San Diego County, 2005, Drainage Design Manual, July, available at:
http://www.sandiegocounty.gov/dpw/floodcontrol/floodcontrolpdf/drainagedesignmanual05.pdf Santa Ana Watershed Project Authority (SAWPA), 2018, One Water One Watershed Plan Update 2018, January, http://www.sawpa.org/wp-content/uploads/2018/11/OWOW-PlanUpdate-2018-PRD.pdf.

Shaw, Ryan, 2020, Inter-Basin Coordination Meeting with Ryan Shaw and Temescal GSA, November 30, Included in Appendix H.

The Nature Conservancy (TNC), 2020, GDE Pulse online map database available at https://gde.codefornature.org/#/map, last accessed July 2020.

Thomasson, H.G., Jr., F.H. Olmsted and E.F. LeRoux, 1960, Geology, water resources and usable ground-water storage capacity of part of Solano County, California. Water-Supply Paper 1464. U.S. Geological Survey, https://pubs.usgs.gov/wsp/1464/report.pdf.

Todd Engineers (Todd), 2011, Technical Study of Potential Stormwater and Surface Water Diversions for Recharge, prepared for the City of Corona and Riverside County, January 31.

Todd Engineers and AKM Consulting Engineers (Todd and AKM), 2008, AB3030 Groundwater Management Plan, prepared for the City of Corona, June.

Todd Groundwater (Todd), H&H Water Resources (H&H), and Stantec, 2021, Groundwater Sustainability Plan, Bedford-Coldwater Basin, May,
https://www.bedfordcoldwatergsa.com/wp-content/uploads/2021/06/Public-DraftBedford-Coldwater-GSP-20210528.pdf.

Towill, Inc. 2020, InSAR Data Accuracy for California Groundwater Basins CGPS Data Comparative Analysis, January 2015 to September 2019, March 23, available at https://data.cnra.ca.gov/dataset/5e2d49e1-9ed0-425e-9f3e2cda4a213c26/resource/a1949b59-2435-4e5d-bb29-7a8d432454f5/download/insar-dataaccuracy-report-towill.pdf.

United States Department of Health and Human Services (USDHHS), 2015, Federal Panel on Community Water Fluoridation, US Public Health Service recommendation for fluoride concentration in drinking water for the prevention of dental caries. Public Health Reports, 130(4), 318-331, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4547570/.

United States Environmental Protection Agency (USEPA), 2019, Contaminants of Emerging Concern including Pharmaceuticals and Personal Care Products, updated August 19, 2019, https://www.epa.gov/wqc/contaminants-emerging-concern-including-pharmaceuticals-andpersonal-care-products, last accessed July 2020.

United States Geological Survey (USGS), 2004, Preliminary Digital Geologic Map of the Santa Ana 30’ x 60’ Quadrangle, Southern California, Version 2.0 compiled by D.M. Morton, OpenFile Report 99-172, http://pubs.usgs.gov/of/1999/of99-172/.

Temescal Basin GSP 10-6
United States Geological Survey (USGS), 2006, Geologic Map of the San Bernardino and Santa Ana 30’ x 60’ Quadrangles, California, Version 1.0 compiled by Douglas M. Morton and Fred K. Miller, Open-File Report 2006-1217, http://pubs.usgs.gov/of/2006/1217/.

United States Geological Survey (USGS), 2020a, National Water Information System (USGS NWIS), http://waterdata.usgs.gov/nwis/sw, last accessed July 2020.

United States Geological Survey (USGS), 2020b, Arsenic and Drinking Water, https://www.usgs.gov/mission-areas/water-resources/science/arsenic-and-drinkingwater?qt-science_center_objects=0#qt-science_center_objects, last accessed July 2020.

United States Geological Survey (USGS), 2021, National Field Manual for the Collection of Water-Quality Data (NFM), available online at: https://www.usgs.gov/mission-areas/waterresources/science/national-field-manual-collection-water-quality-data-nfm?qtscience_center_objects=0#qt-science_center_objects, last accessed February 2021.

Water Systems Consulting, Inc. (WSC), Western Municipal Water District 2020 Urban Water Management Plan, June 16, available at:
https://www.wmwd.com/DocumentCenter/View/5433
Wildermuth Environmental, Inc. (WEI), 2005, Chino Basin Optimum Basin Management Program, State of the Basin Report – 2004, prepared for the Chino Basin Watermaster, July, available at: http://www.cbwm.org/docs/engdocs/isob/ISOB_Final_FullVersion.pdf.

Wildermuth Environmental, Inc. (WEI), 2013, Recharge Master Plan for the Temescal Basin, prepared for the City of Corona, September.

Wildermuth Environmental, Inc. (WEI), 2015, Draft Feasibility Investigation (Phase I) to Develop a Potable Water-Supply from the Bedford Basin, prepared for the City of Corona, Elsinore Valley Water District, and Lee Lake Water District, August.

Wildermuth Environmental, Inc. (WEI), 2016, 2016 Adaptive Management Plan for the Prado Basin Habitat Sustainability Program, prepared for Inland Empire Utilities Agency and Chino Basin Watermaster, August 1.

Wildermuth Environmental, Inc. (WEI), 2017, Salt and Nutrient Management Plan for the Upper Temescal Valley, submitted by Elsinore Valley Municipal Water District and Eastern Municipal Water District, September.

Wildermuth Environmental, Inc. (WEI), 2019, Chino Basin Optimum Basin Management Program, 2018 State of the Basin Report, prepared for the Chino Basin Watermaster, June.

Wildermuth Environmental, Inc. (WEI), 2020, Annual report of the Prado Basin Habitat Sustainability Program, Water year 2019, prepared for Inland Empire Utilities Agency and Chino Basin Watermaster.

Temescal Basin GSP

APPENDIX A
Memorandum of Understanding forming the
Temescal Groundwater Sustainability Agency

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MEMORANDUM OF UNDERSTANDING
(TEMESCAL SUB-BASIN GROUNDWATER SUSTAINABILITY AGENCY)

1. PARTIES AND DATE.

This Memorandum of Understanding (“MOU”) is made and entered into by and between the City of Corona, a municipal corporation organized under the laws of the State of California with its principal place of business at 400 South Vicentia Avenue, Corona, California 92882 (“Corona”), the City of Norco, a municipal corporation organized under the laws of the State of California with its principal place of business at 2870 Clark Avenue, Norco, California 92860 (“Norco”) and the Home Gardens County Water District, a county water district with its principal place of business at 3832 Grant Street, Corona, CA 92879 (“HGCWD”). Corona, Norco and HGCWD are sometimes individually referred to as “Party” and collectively as “Parties” in this MOU.

2. RECITALS.

2.1 Adoption of SGMA. On September 16, 2014, Governor Jerry Brown signed into law Senate Bills 1168 and 1319 and Assembly Bill 1739, known collectively as the Sustainable Groundwater Management Act (“SGMA”).

2.2 Purpose of SGMA. The purpose of SGMA is to create a comprehensive management system in the State of California by creating a structure to manage groundwater at the local level, while providing authority to the State to oversee and regulate, if necessary, the local groundwater management system.

2.3 Groundwater Management Plans. SGMA empowers local agencies to adopt groundwater management plans that are tailored to the resources and needs of their communities to provide a buffer against drought and contribute to reliable water supply for the future.

2.4 Groundwater Sustainability Agencies. Water Code Section 10723.6 authorizes a combination of local agencies overlying a groundwater basin to elect to become a Groundwater Sustainability Agency (“GSA”) by using a memorandum of understanding or other legal agreement.

2.5 Corona’s Authority. Corona is a local agency qualified to become a GSA because Corona manages water, has a water supply, and has land use responsibilities over a portion of the Temescal Sub-Basin of the Upper Santa Ana Valley Groundwater Basin (DWR Basin Number 8-2.09) (“Sub-Basin”), which is a DWR-designated medium priority basin.

2.6 Norco’s Authority. Norco is also a local agency qualified to become a GSA because Norco manages water, has a water supply, and has land use responsibilities over a portion of the Sub-Basin.

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2.7 HGCWD’s Authority.HGCWD is also a local agency qualified to become a GSA because HGCWD is a county water district formed and operating pursuant to and in accordance with Division 12 of the California Water Code that manages water, has a water supply and overlies a portion of the Sub-Basin.

2.8 Corona’s Election to Join GSA. On March 15, 2017, Corona held a public hearing to determine whether to become a GSA, and adopted Resolution No. 2017-013, electing to jointly become a GSA with Norco and HGCWD, a copy of which (without exhibits) is attached hereto as Exhibit “A-1” attached hereto and incorporated herein by reference.

2.9 Norco’s Election to Join GSA. On March 15, 2017, Norco held a public hearing to determine whether to become a GSA, and adopted Resolution No. 2017-12, electing to jointly become a GSA with Corona and HGCWD, a copy of which is attached hereto as Exhibit “A-2” attached hereto and incorporated herein by reference.

2.10 HGCWD’s Election to Join GSA. On March 23, 2017, HGCWD held a public hearing to determine whether to become a GSA, and, by minute action, elected to jointly become a GSA with Corona and Norco.

2.11 Submission of Notice of Decision. Corona, Norco and HGCWD will jointly submit a Notice of Decision to form and be the founding Parties of a GSA, which will cover the Sub-Basin as shown on the map in Exhibit “B-1” attached hereto and incorporated herein by reference.

2.12 Boundaries of Sub-Basin. Additional detail identifying boundaries of the Parties and agencies covering the Sub-Basin is shown on the map attached as Exhibit “B-2” attached hereto and incorporated herein by reference.

2.13 Preparation of Groundwater Sustainability Plan for Sub-Basin. The Parties will work collaboratively with other interested agencies to develop and implement a Groundwater Sustainability Plan (“GSP”) to sustainably manage the Sub-Basin pursuant to SGMA.

2.14 Corona Utility Authority. The Parties to this MOU understands that Corona has entered into a Water Enterprise Management Agreement and a Wastewater Enterprise Management Agreement, both dated as of February 6, 2002, with the Corona Utility Authority (“CUA”) for the maintenance, management and operation of those utility systems (collectively, the “Corona Management Agreements”). To the extent that this MOU is deemed to be a "material contract" under either of the Corona Management Agreements, Corona enters into this MOU on behalf of the CUA and subject to the terms of the applicable Corona Management Agreement(s).

3. TERMS.

3.1 Purpose. This MOU is entered into by and between the Parties to facilitate a cooperative and ongoing working relationship that will allow compliance with the SGMA and other applicable State law, both as may be amended from time to time.

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3.2 Temescal Sub-Basin Groundwater Sustainability Agency. The Parties hereby establish the Temescal Sub-Basin Groundwater Sustainability Agency (“Temescal GSA”) to manage the portion of the Sub-Basin as set forth in Exhibit “B-1” attached hereto and incorporated herein by reference.

3.3 Additional Agencies. Additional agencies with service area boundaries outside the jurisdiction of the Parties may join and incorporate their service area boundaries or portions thereof into the Temescal GSA upon the mutual consent of all Parties. The additional agencies will be added to Exhibit “C-1” attached hereto and incorporated herein by reference, as amended from time to time in compliance with SGMA, and the boundaries of the Temescal GSA may be expanded accordingly.

3.4 Powers. In addition to any other action available to develop and implement the SGMA, including a GSP, the Temescal GSA may perform the following functions:

A. Adopt standards for measuring and reporting water use.

B. Develop and implement policies designed to reduce or eliminate overdraft within the boundaries of the GSA.

C. Develop and implement conservation best management practices.

D. Develop and implement metering, monitoring and reporting related to groundwater pumping.

E. Exercise any and all powers described in Part 2.74 of Division 6 of the Water Code, the Sustainable Groundwater Management Act.

3.5 Decision Making Process.

3.5.1 Majority Vote Required. Each party shall have one vote through its representative designated pursuant to Section 3.7 of this MOU. With the exceptions noted herein, it is the preference of the Parties that actions undertaken by the Temescal GSA are done by unanimous consent of the Parties; however, if unanimous consent is not possible, a majority vote of all then current Parties to this MOU is required.

3.5.2 Impasse Procedures. In the event of an impasse or disagreement where a majority vote cannot be reached, the Parties shall use their best efforts to find a mutually agreeable result. To this effect, the Parties shall consult and negotiate with each other in good faith in an attempt to reach a solution that is mutually satisfactory. If the Parties do not reach a solution that is acceptable to a majority of all then current Parties to this MOU, then the matter shall be submitted to non-binding arbitration or mediation within a reasonable period of time.

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3.6 Roles and Responsibilities of the Parties.

A. Corona shall have the primary responsibility to develop a GSP within the boundaries of the Temescal GSA and submit the GSP to the California Department of Water Resources (“DWR”) for review and evaluation.

Corona shall also have the primary responsibility to prepare and submit the annual and five year reports to DWR pursuant to SGMA and DWR’s implementing regulations.

B. The Parties will work jointly to fulfill the purpose of this MOU within the boundaries of the Temescal GSA.

C. The Parties will meet regularly to discuss SGMA, GSP development and implementation activities, assignments, and ongoing work progress.

D. The Parties may form committees as necessary from time to time to discuss issues that impact the Temescal GSA.

E. Corona is responsible for implementing the GSP in areas of the Temescal GSA that are within Corona’s service area boundaries and within Corona’s sphere of influence.

F. Norco is responsible for implementing the GSP in areas of the Temescal GSA that are within Norco’s service area boundaries.

G. HGCWD is responsible for implementing the GSP in areas of the Temescal GSA that are within HGCWD’s service area boundaries.

3.7 Designation of Representatives.

3.7.1 Corona’s Representative. Corona hereby designates Tom Moody, or his or her designee, to act as its representative for the performance of this MOU (“Corona’s Representative”). Corona’s Representative shall have the power to act on behalf of the Corona for all purposes under this MOU. Corona’s Representative may be changed at any time by providing notice to the other Parties pursuant to Section 3.12.

3.7.2 Norco’s Representative. Norco hereby designates Chad Blais, or his or her designee, to act as its representative for the performance of this MOU (“Norco’s Representative”). Norco’s Representative shall have the power to act on behalf of the Norco for all purposes under this MOU. Norco’s Representative may be changed at any time by providing notice to the other Parties pursuant to Section 3.12.

3.7.3 HGCWD’s Representative. HGCWD hereby designates David Vigil, or his or her designee, to act as its representative for the performance of this MOU (“HGCWD’s Representative”). HGCWD’s Representative shall have the power to act on behalf of HGCWD for all purposes under this MOU. HGCWD’s Representative may be changed at any time by providing notice to the other Parties pursuant to Section 3.12.

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3.8 Funding. Unless agreed to otherwise, each Party’s participation in this MOU is at its sole cost and expense. Each Party shall be financially responsible for collecting data or information from within that Party’s service area that is required to be provided for development of the GSP. Norco and HGCWD shall not incur any financial expense related to development of the GSP and submittal of the GSP to the DWR.

3.9 Term and Termination. This MOU shall remain in effect unless terminated by the mutual written consent of the Parties. Any Party may elect to withdraw its participation in the Temescal GSA by providing sixty (60) days’ written notice to the other Parties.

Additionally, the Parties may mutually agree to terminate this MOU and instead enter into a joint powers agreement pursuant to the Joint Exercise of Powers Act, Government Code Section 6500 et seq. for the purpose of creating a separate public agency to serve as the Temescal GSA and carry out all obligations and exercise all powers under SGMA.

3.10 Amending the MOU. This MOU and Exhibits hereto may only be amended by a subsequent writing, approved and signed by all Parties.

3.11 Hold Harmless and Mutual Indemnification. No Party, nor any officer or employee of a Party, shall be responsible for any damage or liability occurring by reason of anything done or omitted to be done by another Party under or in connection with this MOU.

Each Party shall defend, indemnify and hold harmless the other Parties and their elected officials, officers, agents and employees from and against any and all claims, demands, judgments or liabilities arising from any and all alleged acts or omissions of the indemnifying Party and its elected officials, officers, agents and employees during those times when said elected officials, officers, agents and employees are acting in connection with this MOU.

3.12 Notices. Except as otherwise expressly provided by law, any and all notices or other communications required or permitted by this MOU to be served on or given to a Party to this MOU shall be in writing and shall be deemed duly served or given when personally delivered to the Party to whom it is directed or to any managing or executive officer or director of that Party. In lieu of personal service, all notices or other communications shall be deemed duly served when sent via electronic mail or when deposited in the United States mail, first class postage prepaid, addressed as follows:

If to Corona: City of Corona
Attn: Department of Water and Power, General Manager
755 Public Safety Way
Corona, CA 92882
E-mail: [email protected]
If to Norco: City of Norco
Attn: Public Works Director
2870 Clark Avenue
Norco, CA 92860
E-mail: [email protected]

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If to HGCWD: Home Gardens County Water District
Attn: General Manager
3832 Grant Street
Corona, CA 92879
E-mail: [email protected]

3.13 Counterparts. This MOU may be signed in counterparts, each of which shall constitute an original.

3.14 Cooperation; Further Acts. The Parties shall fully cooperate with one another, and shall take any additional acts or sign any additional documents as may be necessary, appropriate or convenient to attain the purposes of this MOU.

3.15 Entire Agreement. This MOU contains the entire agreement of the Parties with respect to the subject matter hereof, and supersedes all prior negotiations, understandings or agreements.

3.16 Corona Utility Authority. To the extent that this MOU is deemed to be a "material contract" under either of the Corona Management Agreements, the Parties to this MOU have no right to terminate this MOU, either with or without cause, based upon the existence or non-existence of either or both of the Corona Management Agreements. Therefore, if an applicable Corona Management Agreement expires or terminates for any reason, the Parties to this MOU shall remain fully obligated to perform under this MOU contracting directly with the CUA or another third party contracted by the CUA for the maintenance, management and operation of the applicable utility system.
[SIGNATURES ON FOLLOWING 3 PAGES]

CA\JR\06100.30901\10173690.7
EXHIBIT “A-1”
TO

MEMORANDUM OF UNDERSTANDING
(TEMESCAL SUB-BASIN GROUNDWATER SUSTAINABILITY AGENCY)

CORONA RESOLUTION ON FORMATION OF THE TEMESCAL SUBBASIN

GROUNDWATER SUSTAINABILITY AGENCY
[SEE ATTACHED FOUR (4) PAGES]

CA\JR\06100.30901\10179374.1
RESOLUTION NO. 2017-013

RESOLUTION OF THE CITY COUNCIL OF THE CITY OF

CORONA AUTHORIZING THE EXECUTION AND

DELIVERY OF A MEMORANDUM OF UNDERSTANDING

WITH THE CITY OF NORCO AND THE HOME GARDENS

COUNTY WATER DISTRICT FOR THE PURPOSE OF

JOINTLY ESTABLISHING AND SERVICING AS THE

TEMESCAL SUB-BASIN GROUNDWATER

SUSTAINABILITY AGENCY
WHEREAS, in September 2014, the Governor signed three bills (SB 1168, SB 1319, and AB 1739) into law creating the Sustainable Groundwater Management Act of 2014 (“SGMA”), which generally requires the formation of one or more Groundwater Sustainability Agencies (“GSA”) responsible for implementing sustainable groundwater management and preventing “undesirable results” in groundwater basins and sub-basins designated as a medium or high or priority basin by the California Department of Water Resources (“DWR”); and WHEREAS, DWR has designated the Temescal Sub-Basin of the Upper Santa Ana Valley Groundwater Basin (the “Sub-Basin”), as a medium priority groundwater basin; and WHEREAS, the City of Corona (“City”), the City of Norco (“Norco”) and the Home Gardens County Water District (“HGWD”) each overlay a portion of the Sub-Basin and each exercise water management, water supply or land use authority within a portion of the SubBasin; and WHEREAS, under SGMA, a combination of local agencies may elect to form a GSA for all or portions of the Sub-Basin through a memorandum of understanding; and WHEREAS, the City, Norco and HGWD have negotiated that certain Memorandum of Understanding (Temescal Sub-Basin Groundwater Sustainability Agency) (“MOU”) by and between the City of Corona, the City of Norco, and the Home Gardens Water District for the purpose of jointly establishing and servicing as the Temescal Sub-Basin Groundwater Sustainability Agency; and
WHEREAS, the Temescal Sub-Basin Groundwater Sustainability Agency will implement SGMA in the entire Sub-Basin; and
WHEREAS, the City held a public hearing on March 15, 2017 pursuant to California Water Code Section 10723(b), after publication of notice of such hearing pursuant to California Government Code Section 6066.

NOW, THEREFORE, BE IT RESOLVED, by the City Council of the City of

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2 Corona, California, as follows:

SECTION 1. Election to Form GSA. The City of Corona hereby elects, jointly with the City of Norco and the Home Gardens Water District, to become the Temescal SubBasin Groundwater Sustainability Agency to serve as the groundwater sustainability agency over the entire Temescal Sub-Basin of the Upper Santa Ana Valley Groundwater Basin pursuant to California Water Code Section 10723.6(a)(2). The Temescal Sub-Basin Groundwater Sustainability Agency shall have all the powers granted to a groundwater sustainability agency pursuant to SGMA. The City, Norco and HGWD will jointly submit to DWR a notice of their decision to form the Temescal Sub-Basin Groundwater Sustainability Agency for the Temescal Sub-Basin of the Upper Santa Ana Valley Groundwater Basin.

SECTION 2. Sub-Basin Boundaries Managed by GSA. The portion of the Temescal Sub-Basin to be managed by the Temescal Sub-Basin Groundwater Sustainability Agency shall be that portion of the Sub-Basin as depicted in Exhibit “A” attached hereto and incorporated herein by reference, which boundary may be modified from time to time.

SECTION 3. Interested Persons. The Temescal Sub-Basin Groundwater Sustainability Agency shall consider the interests of all beneficial users and users of groundwater, as well as those responsible for implementing groundwater sustainability plans, as required by California Water Code Section 10723.2. The Temescal Sub-Basin Groundwater Sustainability Agency shall establish and maintain a list of persons interested in receiving notices regarding preparation of the GSP, meeting announcements, and availability of draft plans, maps, and other documents, as required by California Water Code Section 10723.4.

SECTION 4. Approval of MOU. The City hereby approves the MOU in substantially the form attached hereto as Exhibit “B” and incorporated herein by reference, which provides the governing structure of the Temescal Sub-Basin Groundwater Sustainability Agency.

SECTION 5. Implementation. The Mayor and the City Clerk are hereby authorized and directed to execute and deliver the MOU for and on behalf of the City, and the Mayor and City staff are authorized to take any actions and execute any documents necessary to carry out the stated purposes of this Resolution, including authorizing non-substantive changes to the MOU, which are approved as to form by the City Attorney.

SECTION 6. Severability. If any provision of this Resolution or the application of any such provision to any person or circumstance is held invalid, such invalidity shall not affect other provisions or applications of this Resolution that can be given effect without the invalid provision or application, and to this end the provisions of this Resolution are severable.

SECTION 7. Effective Date. This Resolution shall become effective immediately upon its adoption.

CA\JR\06100.30901\10173690.7
EXHIBIT “A-2”
TO

MEMORANDUM OF UNDERSTANDING
(TEMESCAL SUB-BASIN GROUNDWATER SUSTAINABILITY AGENCY)

NORCO RESOLUTION ON FORMATION OF THE TEMESCAL SUBBASIN

GROUNDWATER SUSTAINABILITY AGENCY
[SEE ATTACHED TWO (2) PAGES]

RESOLUTION NO. 2017-12

A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF NORCO,

CALIFORNIA, APPROVING A MEMORANDUM OF UNDERSTANDING
(MOU) BETWEEN THE CITY OF CORONA, HOME GARDENS COUNTY

WATER DISTRICT AND THE CITY OF NORCO FOR THE

ESTABLISHMENT OF THE TEMESCAL SUB-BASIN GROUNDWATER

SUSTAINABILITY AGENCY, LOCATED IN NORCO, CALIFORNIA
WHEREAS, On September 16, 2014, Governor Jerry Brown signed into law Senate Bills 1168 and 1319 and Assembly Bill 1739, known collectively as the Sustainable Groundwater Management Act (“SGMA”); and
WHEREAS, the Sustainable Groundwater Management Act (SGMA) is for groundwater to be managed sustainably in California’s groundwater basins (California Water Code Sections 10733.2, et seq.) requires urban water suppliers to prepare and adopt groundwater sustainability plans (GSPs); and
WHEREAS, the Sustainable Groundwater Management Act requires that groundwater sustainability plans are to be prepared and submitted by January 31, 2020 by medium and priority groundwater basins; and
WHEREAS, the Department of Water Resources has determined the Temescal Basin to be a medium priority basin under the Sustainable Groundwater Management Act; and
WHEREAS, the Temescal Basin is not an adjudicated basin and the City of Norco is required to prepare a groundwater sustainability plan as an individual agency or with all agencies who extract groundwater from the basin as required by the Sustainable Groundwater Management Act; and
WHEREAS, the City of Corona, Home Gardens County Water District and the City of Norco desire to establish the Temescal Sub-Basin Groundwater Sustainability Agency to manage the Temescal groundwater basin; and
NOW, THEREFORE, BE IT RESOLVED that the Council of the City of Norco approve the Memorandum of Understanding to establish the Temescal Sub-Basin Groundwater Sustainability Agency.

CA\JR\06100.30901\10173690.7
EXHIBIT “B-1”
TO

MEMORANDUM OF UNDERSTANDING
(TEMESCAL SUB-BASIN GROUNDWATER SUSTAINABILITY AGENCY)

MAP OF TEMESCAL SUB-BASIN
[SEE ATTACHED ONE (1) PAGE]

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EXHIBIT “B-2”
TO

MEMORANDUM OF UNDERSTANDING
(TEMESCAL SUB-BASIN GROUNDWATER SUSTAINABILITY AGENCY)
MAP OF PARTIES’ SERVICE AREAS

WITHIN THE TEMESCAL SUB-BASIN
[SEE ATTACHED ONE (1) PAGE]

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Temescal Basin GSP

APPENDIX B
Temescal GSA Notice of Decision to become a
Groundwater Sustainability Agency

THIS SPACE RESERVED FOR CLERK / RECORDING STAMP

PROOF OF PUBLICATION
(2010, 2015.5 C.C.P.)

STATE OF CALIFORNIA

COUNTY OF RIVERSIDE
I am a Citizen of the United States. I am over the age of eighteen years and not a party to or interested in the above entitled matter. I am an Authorized Representative of SENTINEL WEEKLY NEWS (formerly known as The Lake Mathews Sentinel), a Newspaper of General Circulation, printed and published weekly in the City of Corona, County of Riverside, and which Newspaper has been Adjudicated a Newspaper of General Circulation by the Superior Court of the County of Riverside, State of California, under the date of March 30, 1995, Case Number 262254; and under the date of December 7, 1999, Case Number 334071; and the Notice, of which the annexed is a printed copy, has been published in said Newspaper in accordance with the instructions of the Person(s) requesting publication, and not in any supplement thereof on the following dates to wit:
(1) March 1, 2017
(2) March 8, 2017
(3)
(4)
I certify (or declare) under penalty of perjury that the foregoing is true and correct.

/S/ ______________________________________
Authorized Representative
DATED: __ MARCH 8, 2017 __

P R O O F O F P U B L I C A T I O N
Sentinel Weekly News
Adjudicated for the City of Corona, California
1307-C West 6
th St., Suite 139
Corona, CA. 92882
Tel: (951) 737-9784 / Fax: (951) 737-9785
E-mail: [email protected]

CITY OF CORONA

OFFICE OF THE CITY CLERK

NOTICE OF PUBLIC HEARING

PUBLIC NOTICE IS HEREBY GIVEN
that the City Council of the City of
Corona, California, and the Corona
Utility Authority will conduct a public
hearing in the Council Chambers, at
City Hall, 400 South Vicentia Avenue, in
said City of Corona,
ON WEDNESDAY, MARCH 15, 2017 AT
6:30 P.M. or thereafter upon the following:

PROPOSED ACTION:

The City Council and the Corona Utility
Authority will consider entering into a
Memorandum of Understanding
(“MOU”) with the City of Norco (“Norco”) and the Home Gardens Water District (“HGWD”) for the purpose of
establishing the Temescal Sub-Basin
Groundwater Sustainability Agency to
serve as the groundwater sustainability
agency for the Temescal Sub-Basin of
the Upper Santa Ana Valley Groundwater Basin (DWR Basin Number 8-2.09) (“Sub-Basin”) pursuant to the requirements of the Sustainable Groundwater Management Act of 2014 (“SGMA”).

The primary purpose of a groundwater
sustainability agency under SGMA is to
develop a groundwater sustainability
plan (“GSP”) to achieve long-term
groundwater sustainability. The parties
to the MOU will work jointly and
cooperatively to serve as the groundwater sustainability agency and to satisfy the requirements of SGMA.

Each party to the MOU will participate
at its sole cost and expense and will be
financially responsible for collecting
data or information from that party’s
service area. The City of Corona will
have the primary responsibility to
develop a GSP and submit it to the
California Department of Water Resources (“DWR”) for review and evaluation.

This is a public hearing and you are
invited to attend and comment on the
application described above. If you
challenge any portion of this project in
court, you may be limited to raising
only those issues you or someone else
raised at the public hearing described
in this notice, or in written correspondence delivered at, or prior to, the public hearing. If you have written comments
that you wish to be included in the staff
report, please deliver them to the City
Clerk, on or before the Tuesday prior to
the meeting. If you have questions
about this notice or the application to
be heard, please call Katie Hockett with
the Department of Water and Power at
(951) 279-3601.
//S// Lisa Mobley, City Clerk
PUBLISHED: March 1, 2017 and March
8, 2017
JOB CC17-019

SENTINEL WEEKLY NEWS
"Adjudicated for City of Corona,
Corona Judicial Dist., Riverside County, California"
SWN-2509 JOB CC17-019
MARCH 1, 8, 2017

Temescal Basin GSP

APPENDIX C
Groundwater Sustainability Plan
Elements Guide

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
§ 354. Introduction to Plan Contents
This Article describes the required contents of Plans submitted to the Department for evaluation, including administrative information, a description of the basin setting, sustainable management criteria, description of the monitoring network, and projects and management actions.

Note: Authority cited: Section 10733.2, Water Code.

Reference: Section 10733.2, Water Code.

SubArticle 1. Administrative Information
§ 354.2. Introduction to Administrative Information
This Subarticle describes information in the Plan relating to administrative and other general information about the Agency that has adopted the Plan and the area covered by the Plan.

Note: Authority cited: Section 10733.2, Water Code.

Reference: Section 10733.2, Water Code.
§ 354.4. General Information
Each Plan shall include the following general information:
(a) An executive summary written in plain language that provides an overview of the Plan and description of groundwater conditions in the basin. ES (b)
A list of references and technical studies relied upon by the Agency in developing the Plan. Each Agency shall provide to the Department electronic copies of reports and other documents and materials cited as references that are not generally available to the public. 10
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10733.2 and 10733.4, Water Code.
§ 354.6. Agency Information
When submitting an adopted Plan to the Department, the Agency shall include a copy of the information provided pursuant to Water Code Section 10723.8, with any updates, if necessary, along with the following information:
(a) The name and mailing address of the Agency. 1.3
(b) The organization and management structure of the Agency, identifying persons with management authority for implementation of the Plan. 1.4 (c) The name and contact information, including the phone number, mailing address and electronic mail address, of the plan manager. 1.3
(d)
The legal authority of the Agency, with specific reference to citations setting forth the duties, powers, and responsibilities of the Agency, demonstrating that the Agency has the legal authority to implement the Plan. 1.4.3
(e) An estimate of the cost of implementing the Plan and a general description of how the Agency plans to meet those costs. 1.4.4
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10723.8, 10727.2, and 10733.2, Water Code. § 354.8. Description of Plan Area
Each Plan shall include a description of the geographic areas covered, including the following information:

GSP Document References

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(a) One or more maps of the basin that depict the following, as applicable:
(1)
The area covered by the Plan, delineating areas managed by the Agency as an exclusive Agency and any areas for which the Agency is not an exclusive Agency, and the name and location of any adjacent basins. 2.1 Figure 1-1
(2) Adjudicated areas, other Agencies within the basin, and areas covered by an Alternative. 2.1 Figure 2-2 (3)
Jurisdictional boundaries of federal or state land (including the identity of the agency with jurisdiction over that land), tribal land, cities, counties, agencies with water management responsibilities, and areas covered by relevant general plans. 2.2 Figure 2-1,
2-2
(4) Existing land use designations and the identification of water use sector and water source type. 2.4.9, 2.3.3,

2.3.2 Figure 2-4,
Figure 2-
10, Figure 2-
11 (5)
The density of wells per square mile, by dasymetric or similar mapping techniques, showing the general distribution of agricultural, industrial, and domestic water supply wells in the basin, including de minimis extractors, and the location and extent of communities dependent upon groundwater, utilizing data provided by the Department, as specified in Section 353.2, or the best available information. 2.1.2.1 Figures 2-
5,2-6, 2-7,
2-8
(b) A written description of the Plan area, including a summary of the jurisdictional areas and other features depicted on the map. 2.1
Figure 2-1,
2-2
(c)
Identification of existing water resource monitoring and management programs, and description of any such programs the Agency plans to incorporate in its monitoring network or in development of its Plan. The Agency may coordinate with existing water resource monitoring and management programs to incorporate and adopt that program as part of the Plan. 2.4
(d)
A description of how existing water resource monitoring or management programs may limit operational flexibility in the basin, and how the Plan has been developed to adapt to those limits. 2.4
(e) A description of conjunctive use programs in the basin. 2.3.2 (f) A plain language description of the land use elements or topic categories of applicable general plans that includes the following:
(1) A summary of general plans and other land use plans governing the basin. 2.6 Figure 2-8,
2-9
(2)
A general description of how implementation of existing land use plans may change water demands within the basin or affect the ability of the Agency to achieve sustainable groundwater management over the planning and implementation horizon, and how the Plan addresses those potential effects 2.6.4
(3) A general description of how implementation of the Plan may affect the water supply assumptions of relevant land use plans over the planning and implementation horizon. 2.6.5

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(4)
A summary of the process for permitting new or replacement wells in the basin, including adopted standards in local well ordinances, zoning codes, and policies contained in adopted land use plans. 2.7.3
(5)
To the extent known, the Agency may include information regarding the implementation of land use plans outside the basin that could affect the ability of the Agency to achieve sustainable groundwater management. 2.7.5
(g) A description of any of the additional Plan elements included in Water Code Section 10727.4 that the Agency determines to be appropriate. 2.7 Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10720.3, 10727.2, 10727.4, 10733, and 10733.2, Water Code. § 354.10. Notice and Communication
Each Plan shall include a summary of information relating to notification and communication by the Agency with other agencies and interested parties including the following:
(a)
A description of the beneficial uses and users of groundwater in the basin, including the land uses and property interests potentially affected by the use of groundwater in the basin, the types of parties representing those interests, and the nature of consultation with those parties.

3.10, 6.2.4,

6.3.4, 6.5.4,

6.6.4, 6.6.7,
Appendix D
(b) A list of public meetings at which the Plan was discussed or considered by the Agency. Appendix E (c) Comments regarding the Plan received by the Agency and a summary of any responses by the Agency. Appendix I
(d) A communication section of the Plan that includes the following:
(1) An explanation of the Agency’s decision-making process. Section

1.4.1,
Appendix A
(2) Identification of opportunities for public engagement and a discussion of how public input and response will be used.

Section 2.8,
Appendices

D, E, F, G,
and H
(3) A description of how the Agency encourages the active involvement of diverse social, cultural, and economic elements of the population within the basin.

Section 2.8,
Appendices

D, E, F, G,
and H

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(4) The method the Agency shall follow to inform the public about progress implementing the Plan, including the status of projects and actions.

Section 2.8,
Appendices

D, E, F, G,
and H
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10723.2, 10727.8, 10728.4, and 10733.2, Water Code SubArticle 2. Basin Setting
§ 354.12. Introduction to Basin Setting
This Subarticle describes the information about the physical setting and characteristics of the basin and current conditions of the basin that shall be part of each Plan, including the identification of data gaps and levels of uncertainty, which comprise the basin setting that serves as the basis for defining and assessing reasonable sustainable management criteria and projects and management actions. Information provided pursuant to this Subarticle shall be prepared by or under the direction of a professional geologist or professional engineer.

Note: Authority cited: Section 10733.2, Water Code.

Reference: Section 10733.2, Water Code.
§ 354.14. Hydrogeologic Conceptual Model
(a)
Each Plan shall include a descriptive hydrogeologic conceptual model of the basin based on technical studies and qualified maps that characterizes the physical components and interaction of the surface water and groundwater systems in the basin. 3 Figures 3-1
through 3-
12 (b) The hydrogeologic conceptual model shall be summarized in a written description that includes the following:
(1) The regional geologic and structural setting of the basin including the immediate surrounding area, as necessary for geologic consistency.

Sections

3.4 and 3.5
Figures 3-1
through 3-
5 (2) Lateral basin boundaries, including major geologic features that significantly affect groundwater flow.

3.5, 3.6,
and 3.7
Figure 3-5,
3-10
(3) The definable bottom of the basin. 3.8 Figure 3-11
(4) Principal aquifers and aquitards, including the following information:
(A) Formation names, if defined. 3.6.1 Figure 3-5
(B)
Physical properties of aquifers and aquitards, including the vertical and lateral extent, hydraulic conductivity, and storativity, which may be based on existing technical studies or other best available information.

3.4, 3.5,

3.6, 3.7,

3.8, and
Appendix J
Figure 3-5,
3-10,
Appendix J
(C)
Structural properties of the basin that restrict groundwater flow within the principal aquifers, including information regarding stratigraphic changes, truncation of units, or other features.

3.4, 3.5,

3.6, 3.7,

3.8, and
Appendix J
Figure 3-5,
3-10,
Appendix J

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(D) General water quality of the principal aquifers, which may be based on information derived from existing technical studies or regulatory programs. 4.4 and 4.5 Figures 4-
15, 4-16
(E) Identification of the primary use or uses of each aquifer, such as domestic, irrigation, or municipal water supply. 3.10 Table 2-1
(5) Identification of data gaps and uncertainty within the hydrogeologic conceptual model 3.11 (c)
The hydrogeologic conceptual model shall be represented graphically by at least two scaled cross-sections that display the information required by this section and are sufficient to depict major stratigraphic and structural features in the basin. 3.6 Figure 3-6
through 3-
9 (d) Physical characteristics of the basin shall be represented on one or more maps that depict the following:
(1) Topographic information derived from the U.S. Geological Survey or another reliable source. Figure 3-1
(2) Surficial geology derived from a qualified map including the locations of cross-sections required by this Section.

Figure 3-5
and Figure
3-6
(3) Soil characteristics as described by the appropriate Natural Resources Conservation Service soil survey or other applicable studies. 3.2 Figure 3-4 (4)
Delineation of existing recharge areas that substantially contribute to the replenishment of the basin, potential recharge areas, and discharge areas, including significant active springs, seeps, and wetlands within or adjacent to the basin. Figure 3-10 (5) Surface water bodies that are significant to the management of the basin.

Figure 3-2
and Figure
3-3
(6) The source and point of delivery for imported water supplies. 2.1.2.1 Figure 2-9 Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10727.2, 10733, and 10733.2, Water Code. § 354.16. Groundwater Conditions
Each Plan shall provide a description of current and historical groundwater conditions in the basin, including data from January 1, 2015, to current conditions, based on the best available information that includes the following:
(a) Groundwater elevation data demonstrating flow directions, lateral and vertical gradients, and regional pumping patterns, including:
(1)
Groundwater elevation contour maps depicting the groundwater table or potentiometric surface associated with the current seasonal high and seasonal low for each principal aquifer within the basin.

Figure 4-10
and Figure
4-11
(2) Hydrographs depicting long-term groundwater elevations, historical highs and lows, and hydraulic gradients between principal aquifers.

Figure 4-2
and Figure
4-9

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(b)
A graph depicting estimates of the change in groundwater in storage, based on data, demonstrating the annual and cumulative change in the volume of groundwater in storage between seasonal high groundwater conditions, including the annual groundwater use and water year type. Figure 5-6
(c) Seawater intrusion conditions in the basin, including maps and cross-sections of the seawater intrusion front for each principal aquifer. 4.9 (d)
Groundwater quality issues that may affect the supply and beneficial uses of groundwater, including a description and map of the location of known groundwater contamination sites and plumes.

4.4, 4.5,

4.6, 4.7,
and 4.8
Figure 4-14
through 4-
16 (e)
The extent, cumulative total, and annual rate of land subsidence, including maps depicting total subsidence, utilizing data available from the Department, as specified in Section 353.2, or the best available information. 4.3
Figure 4-12
and 4-13
(f)
Identification of interconnected surface water systems within the basin and an estimate of the quantity and timing of depletions of those systems, utilizing data available from the Department, as specified in Section 353.2, or the best available information. 4.10 Figures 4-
17 through
4-23
(g)
Identification of groundwater dependent ecosystems within the basin, utilizing data available from the Department, as specified in Section 353.2, or the best available information. 4.10
Figures 4-
17 through
4-23
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10723.2, 10727.2, 10727.4, and 10733.2, Water Code. § 354.18. Water Budget
(a)
Each Plan shall include a water budget for the basin that provides an accounting and assessment of the total annual volume of groundwater and surface water entering and leaving the basin, including historical, current and projected water budget conditions, and the change in the volume of water stored. Water budget information shall be reported in tabular and graphical form. 5.1, 5.5
Figure 5-5
and 5-6
(b) The water budget shall quantify the following, either through direct measurements or estimates based on data:
(1) Total surface water entering and leaving a basin by water source type. 5.6 Figure 5-4 Table 5-3 (2)
Inflow to the groundwater system by water source type, including subsurface groundwater inflow and infiltration of precipitation, applied water, and surface water systems, such as lakes, streams, rivers, canals, springs and conveyance systems. 5.7.1 Figure 5-6 Table 5-4 (3)
Outflows from the groundwater system by water use sector, including evapotranspiration, groundwater extraction, groundwater discharge to surface water sources, and subsurface groundwater outflow. 5.7.2 Figure 5-6 Table 5-4 (4) The change in the annual volume of groundwater in storage between seasonal high conditions. 5.8,
Appendix J Figure 5-6 Table 5-4

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(5)
If overdraft conditions occur, as defined in Bulletin 118, the water budget shall include a quantification of overdraft over a period of years during which water year and water supply conditions approximate average conditions. NA
(6) The water year type associated with the annual supply, demand, and change in groundwater stored. 5.2 Figure 5-1
(7) An estimate of sustainable yield for the basin. 5.9 Table 5-5 (c) Each Plan shall quantify the current, historical, and projected water budget for the basin as follows:
(1)
Current water budget information shall quantify current inflows and outflows for the basin using the most recent hydrology, water supply, water demand, and land use information. 5.7 Figure 5-6 Table 5-4
(2)
Historical water budget information shall be used to evaluate availability or reliability of past surface water supply deliveries and aquifer response to water supply and demand trends relative to water year type. The historical water budget shall include the following:
(A)
A quantitative evaluation of the availability or reliability of historical surface water supply deliveries as a function of the historical planned versus actual annual surface water deliveries, by surface water source and water year type, and based on the most recent ten years of surface water supply information.

Section

2.3.2, 5.7,
Appendix J Figure 5-6 Table 5-4
(B)
A quantitative assessment of the historical water budget, starting with the most recently available information and extending back a minimum of 10 years, or as is sufficient to calibrate and reduce the uncertainty of the tools and methods used to estimate and project future water budget information and future aquifer response to proposed sustainable groundwater management practices over the planning and implementation horizon.

5.7,
Appendix J Figure 5-6 Table 5-4
(C)
A description of how historical conditions concerning hydrology, water demand, and surface water supply availability or reliability have impacted the ability of the Agency to operate the basin within sustainable yield. Basin hydrology may be characterized and evaluated using water year type. 5.8, 5.9
Figure 5-6,
Figure 5-1 Table 5-4
(3)
Projected water budgets shall be used to estimate future baseline conditions of supply, demand, and aquifer response to Plan implementation, and to identify the uncertainties of these projected water budget components. The projected water budget shall utilize the following methodologies and assumptions to estimate future baseline conditions concerning hydrology, water demand and surface water supply availability or reliability over the planning and implementation horizon:
(A)
Projected hydrology shall utilize 50 years of historical precipitation, evapotranspiration, and streamflow information as the baseline condition for estimating future hydrology.

The projected hydrology information shall also be applied as the baseline condition used to evaluate future scenarios of hydrologic uncertainty associated with projections of climate change and sea level rise. 5.3, 5.6, 5.7
Figures 5-
7,5-8,5-10

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(B)
Projected water demand shall utilize the most recent land use, evapotranspiration, and crop coefficient information as the baseline condition for estimating future water demand. The projected water demand information shall also be applied as the baseline condition used to evaluate future scenarios of water demand uncertainty associated with projected changes in local land use planning, population growth, and climate. 5.3, 5.6, 5.7 Figures 5-
7,5-8,5-10 Table 5-2
(C)
Projected surface water supply shall utilize the most recent water supply information as the baseline condition for estimating future surface water supply. The projected surface water supply shall also be applied as the baseline condition used to evaluate future scenarios of surface water supply availability and reliability as a function of the historical surface water supply identified in Section 354.18(c)(2)(A), and the projected changes in local land use planning, population growth, and climate.

5.5, 5.6,

5.7,
Appendix J
Figures 5-
7,5-8,5-10
(d)
The Agency shall utilize the following information provided, as available, by the Department pursuant to Section 353.2, or other data of comparable quality, to develop the water budget:
(1) Historical water budget information for mean annual temperature, mean annual precipitation, water year type, and land use. 5.2,
Appendix J Figure 5-6
(2) Current water budget information for temperature, water year type, evapotranspiration, and land use. 5.2,5.3,
Appendix J Figure 5-6
(3) Projected water budget information for population, population growth, climate change, and sea level rise. 5.5.3,
Appendix J
Figure 5-7
and 5-8
(e)
Each Plan shall rely on the best available information and best available science to quantify the water budget for the basin in order to provide an understanding of historical and projected hydrology, water demand, water supply, land use, population, climate change, sea level rise, groundwater and surface water interaction, and subsurface groundwater flow. If a numerical groundwater and surface water model is not used to quantify and evaluate the projected water budget conditions and the potential impacts to beneficial uses and users of groundwater, the Plan shall identify and describe an equally effective method, tool, or analytical model to evaluate projected water budget conditions.

5.5, 5.6,

5.7, 5.8,
Appendix J
(f)
The Department shall provide the California Central Valley Groundwater-Surface Water Simulation Model (C2VSIM) and the Integrated Water Flow Model (IWFM) for use by Agencies in developing the water budget. Each Agency may choose to use a different groundwater and surface water model, pursuant to Section 352.4.

5.1,
Appendix J
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10721, 10723.2, 10727.2, 10727.6, 10729, and 10733.2, Water Code.
§ 354.20. Management Areas

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(a)
Each Agency may define one or more management areas within a basin if the Agency has determined that creation of management areas will facilitate implementation of the Plan. Management areas may define different minimum thresholds and be operated to different measurable objectives than the basin at large, provided that undesirable results are defined consistently throughout the basin. NA (b) A basin that includes one or more management areas shall describe the following in the Plan:
(1) The reason for the creation of each management area. NA (2)
The minimum thresholds and measurable objectives established for each management area, and an explanation of the rationale for selecting those values, if different from the basin at large. NA
(3) The level of monitoring and analysis appropriate for each management area. NA (4)
An explanation of how the management area can operate under different minimum thresholds and measurable objectives without causing undesirable results outside the management area, if applicable. NA
(c)
If a Plan includes one or more management areas, the Plan shall include descriptions, maps, and other information required by this Subarticle sufficient to describe conditions in those areas. NA
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10733.2 and 10733.4, Water Code.

SubArticle 3. Sustainable Management Criteria
§ 354.22. Introduction to Sustainable Management Criteria This Subarticle describes criteria by which an Agency defines conditions in its Plan that constitute sustainable groundwater management for the basin, including the process by which the Agency shall characterize undesirable results, and establish minimum thresholds and measurable objectives for each applicable sustainability indicator.

Note: Authority cited: Section 10733.2, Water Code.

Reference: Section 10733.2, Water Code.
§ 354.24. Sustainability Goal
Each Agency shall establish in its Plan a sustainability goal for the basin that culminates in the absence of undesirable results within 20 years of the applicable statutory deadline. The Plan shall include a description of the sustainability goal, including information from the basin setting used to establish the sustainability goal, a discussion of the measures that will be implemented to ensure that the basin will be operated within its sustainable yield, and an explanation of how the sustainability goal is likely to be achieved within 20 years of Plan implementation and is likely to be maintained through the planning and implementation horizon. 6.1.1
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10721, 10727, 10727.2, 10733.2, and 10733.8, Water Code. § 354.26. Undesirable Results

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(a)
Each Agency shall describe in its Plan the processes and criteria relied upon to define undesirable results applicable to the basin. Undesirable results occur when significant and unreasonable effects for any of the sustainability indicators are caused by groundwater conditions occurring throughout the basin.

6.2.1, 6.3.1,

6.5.1, 6.6.1,

6.7.1 (b) The description of undesirable results shall include the following:
(1)
The cause of groundwater conditions occurring throughout the basin that would lead to or has led to undesirable results based on information described in the basin setting, and other data or models as appropriate.

6.2.2, 6.3.2,

6.5.2, 6.6.2,

6.7.2 (2)
The criteria used to define when and where the effects of the groundwater conditions cause undesirable results for each applicable sustainability indicator. The criteria shall be based on a quantitative description of the combination of minimum threshold exceedances that cause significant and unreasonable effects in the basin.

6.2.3, 6.3.3,

6.5.3, 6.6.3,

6.7.3 (3)
Potential effects on the beneficial uses and users of groundwater, on land uses and property interests, and other potential effects that may occur or are occurring from undesirable results.

6.2.4, 6.3.4,

6.5.4, 6.6.4,

6.7.4 (c)
The Agency may need to evaluate multiple minimum thresholds to determine whether an undesirable result is occurring in the basin. The determination that undesirable results are occurring may depend upon measurements from multiple monitoring sites, rather than a single monitoring site.

6.2.5, 6.3.5,

6.5.5, 6.6.5,

6.7.5 (d)
An Agency that is able to demonstrate that undesirable results related to one or more sustainability indicators are not present and are not likely to occur in a basin shall not be required to establish criteria for undesirable results related to those sustainability indicators. 6.4
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10721, 10723.2, 10727.2, 10733.2, and 10733.8, Water Code. § 354.28. Minimum Thresholds
(a)
Each Agency in its Plan shall establish minimum thresholds that quantify groundwater conditions for each applicable sustainability indicator at each monitoring site or representative monitoring site established pursuant to Section 354.36. The numeric value used to define minimum thresholds shall represent a point in the basin that, if exceeded, may cause undesirable results as described in Section 354.26.

6.2.6, 6.3.6,

6.5.6, 6.6.6,

6.7.6 (b) The description of minimum thresholds shall include the following:

Article 5. Plan Contents for Temescal Basin
Page
Numbers
of Plan
Or Section
Numbers
Or Figure
Numbers
Or Table
Numbers Notes
GSP Document References
(1)
The information and criteria relied upon to establish and justify the minimum thresholds for each sustainability indicator. The justification for the minimum threshold shall be supported by information provided in the basin setting, and other data or models as appropriate, and qualified by uncertainty in the understanding of the basin setting.

6.2.5, 6.3.5,

6.5.5, 6.6.5,

6.7.5 (2)
The relationship between the minimum thresholds for each sustainability indicator, including an explanation of how the Agency has determined that basin conditions at each minimum threshold will avoid undesirable results for each of the sustainability indicators.

6.2.6, 6.3.6,

6.5.6, 6.6.6,

6.7.6 (3) How minimum thresholds have been selected to avoid causing undesirable results in adjacent basins or affecting the ability of adjacent basins to achieve sustainability goals. 6.2.6, 6.3.6,

6.5.6, 6.6.6,

6.7.6 (4) How minimum thresholds may affect the interests of beneficial uses and users of groundwater or land uses and property interests. 6.2.6, 6.3.6,

6.5.6, 6.6.6,

6.7.6 (5)
How state, federal, or local standards relate to the relevant sustainability indicator. If the minimum threshold differs from other regulatory standards, the Agency shall explain the nature of and basis for the difference.

6.2.6, 6.3.6,

6.5.6, 6.6.6,

6.7.6 (6) How each minimum threshold will be quantitatively measured, consistent with the monitoring network requirements described in Subarticle 4. 6.2.6, 6.3.6,

6.5.6, 6.6.6,

6.7.6 (c) Minimum thresholds for each sustainability indicator shall be defined as follows:
(1)
Chronic Lowering of Groundwater Levels. The minimum threshold for chronic lowering of groundwater levels shall be the groundwater elevation indicating a depletion of supply at a given location that may lead to undesirable results. Minimum thresholds for chronic lowering of groundwater levels shall be supported by the following:
(A) The rate of groundwater elevation decline based on historical trends, water year type, and projected water use in the basin.

4.1.3, 6.2
Figure 4-2
through 4-
9, Figure 6-
1 (B) Potential effects on other sustainability indicators. 6.2.6.2

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(2)
Reduction of Groundwater Storage. The minimum threshold for reduction of groundwater storage shall be a total volume of groundwater that can be withdrawn from the basin without causing conditions that may lead to undesirable results.

Minimum thresholds for reduction of groundwater storage shall be supported by the sustainable yield of the basin, calculated based on historical trends, water year type, and projected water use in the basin. 6.3
(3)
Seawater Intrusion. The minimum threshold for seawater intrusion shall be defined by a chloride concentration isocontour for each principal aquifer where seawater intrusion may lead to undesirable results. Minimum thresholds for seawater intrusion shall be supported by the following:
(A) Maps and cross-sections of the chloride concentration isocontour that defines the minimum threshold and measurable objective for each principal aquifer. 6.4 (B) A description of how the seawater intrusion minimum threshold considers the effects of current and projected sea levels. 6.4
(4)
Degraded Water Quality. The minimum threshold for degraded water quality shall be the degradation of water quality, including the migration of contaminant plumes that impair water supplies or other indicator of water quality as determined by the Agency that may lead to undesirable results. The minimum threshold shall be based on the number of supply wells, a volume of water, or a location of an isocontour that exceeds concentrations of constituents determined by the Agency to be of concern for the basin.

In setting minimum thresholds for degraded water quality, the Agency shall consider local, state, and federal water quality standards applicable to the basin. 6.5 (5)
Land Subsidence. The minimum threshold for land subsidence shall be the rate and extent of subsidence that substantially interferes with surface land uses and may lead to undesirable results. Minimum thresholds for land subsidence shall be supported by the following:
(A)
Identification of land uses and property interests that have been affected or are likely to be affected by land subsidence in the basin, including an explanation of how the Agency has determined and considered those uses and interests, and the Agency’s rationale for establishing minimum thresholds in light of those effects. 6.6 (B) Maps and graphs showing the extent and rate of land subsidence in the basin that defines the minimum threshold and measurable objectives. 6.6 Figure 4-10 (6)
Depletions of Interconnected Surface Water. The minimum threshold for depletions of interconnected surface water shall be the rate or volume of surface water depletions caused by groundwater use that has adverse impacts on beneficial uses of the surface water and may lead to undesirable results. The minimum threshold established for depletions of interconnected surface water shall be supported by the following:
(A) The location, quantity, and timing of depletions of interconnected surface water.

6.7 Figures 4-
17 through
4-23

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(B)
A description of the groundwater and surface water model used to quantify surface water depletion. If a numerical groundwater and surface water model is not used to quantify surface water depletion, the Plan shall identify and describe an equally effective method, tool, or analytical model to accomplish the requirements of this Paragraph. 6.7.5 Figures 4-
17 through
4-23
(d)
An Agency may establish a representative minimum threshold for groundwater elevation to serve as the value for multiple sustainability indicators, where the Agency can demonstrate that the representative value is a reasonable proxy for multiple individual minimum thresholds as supported by adequate evidence. 6.3 (e)
An Agency that has demonstrated that undesirable results related to one or more sustainability indicators are not present and are not likely to occur in a basin, as described in Section 354.26, shall not be required to establish minimum thresholds related to those sustainability indicators. 6.4
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10723.2, 10727.2, 10733, 10733.2, and 10733.8, Water Code. § 354.30. Measurable Objectives
(a)
Each Agency shall establish measurable objectives, including interim milestones in increments of five years, to achieve the sustainability goal for the basin within 20 years of Plan implementation and to continue to sustainably manage the groundwater basin over the planning and implementation horizon.

6.2.7, 6.3.7,

6.5.7, 6.6.7,

6.7.7 (b)
Measurable objectives shall be established for each sustainability indicator, based on quantitative values using the same metrics and monitoring sites as are used to define the minimum thresholds.

6.2.7, 6.3.7,

6.5.7, 6.6.7,

6.7.7 (c)
Measurable objectives shall provide a reasonable margin of operational flexibility under adverse conditions which shall take into consideration components such as historical water budgets, seasonal and long-term trends, and periods of drought, and be commensurate with levels of uncertainty.

6.2.7, 6.3.7,

6.5.7, 6.6.7,

6.7.7 (d)
An Agency may establish a representative measurable objective for groundwater elevation to serve as the value for multiple sustainability indicators where the Agency can demonstrate that the representative value is a reasonable proxy for multiple individual measurable objectives as supported by adequate evidence. 6.3.7 (e)
Each Plan shall describe a reasonable path to achieve the sustainability goal for the basin within 20 years of Plan implementation, including a description of interim milestones for each relevant sustainability indicator, using the same metric as the measurable objective, in increments of five years. The description shall explain how the Plan is likely to maintain sustainable groundwater management over the planning and implementation horizon. 6.1

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(f)
Each Plan may include measurable objectives and interim milestones for additional Plan elements described in Water Code Section 10727.4 where the Agency determines such measures are appropriate for sustainable groundwater management in the basin.

6.2.7, 6.3.7,

6.5.7, 6.6.7,

6.7.7 (g)
An Agency may establish measurable objectives that exceed the reasonable margin of operational flexibility for the purpose of improving overall conditions in the basin, but failure to achieve those objectives shall not be grounds for a finding of inadequacy of the Plan.

6.2.7, 6.3.7,

6.5.7, 6.6.7,

6.7.7 Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10727.2, 10727.4, and 10733.2, Water Code.

SubArticle 4. Monitoring Networks
§ 354.32. Introduction to Monitoring Networks
This Subarticle describes the monitoring network that shall be developed for each basin, including monitoring objectives, monitoring protocols, and data reporting requirements.

The monitoring network shall promote the collection of data of sufficient quality, frequency, and distribution to characterize groundwater and related surface water conditions in the basin and evaluate changing conditions that occur through implementation of the Plan.

Note: Authority cited: Section 10733.2, Water Code.

Reference: Section 10733.2, Water Code.
§ 354.34. Monitoring Network
(a)
Each Agency shall develop a monitoring network capable of collecting sufficient data to demonstrate short-term, seasonal, and long-term trends in groundwater and related surface conditions, and yield representative information about groundwater conditions as necessary to evaluate Plan implementation. 7.1 Table 7-1 (b)
Each Plan shall include a description of the monitoring network objectives for the basin, including an explanation of how the network will be developed and implemented to monitor groundwater and related surface conditions, and the interconnection of surface water and groundwater, with sufficient temporal frequency and spatial density to evaluate the affects and effectiveness of Plan implementation. The monitoring network objectives shall be implemented to accomplish the following:
(1) Demonstrate progress toward achieving measurable objectives described in the Plan. 7.1 Table 7-1 (2) Monitor impacts to the beneficial uses or users of groundwater. 7.1 Table 7-1 (3) Monitor changes in groundwater conditions relative to measurable objectives and minimum thresholds. 7.1 Table 7-1
(4) Quantify annual changes in water budget components. 7.1 Table 7-1 (c) Each monitoring network shall be designed to accomplish the following for each sustainability indicator:

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(1)
Chronic Lowering of Groundwater Levels. Demonstrate groundwater occurrence, flow directions, and hydraulic gradients between principal aquifers and surface water features by the following methods:
(A)
A sufficient density of monitoring wells to collect representative measurements through depth-discrete perforated intervals to characterize the groundwater table or potentiometric surface for each principal aquifer. 7.1.1 Figure 7-1 Table 7-2 (B) Static groundwater elevation measurements shall be collected at least two times per year, to represent seasonal low and seasonal high groundwater conditions. 7.1.1 Figure 7-1 Table 7-2 (2) Reduction of Groundwater Storage. Provide an estimate of the change in annual groundwater in storage. 7.1.2
(3)
Seawater Intrusion. Monitor seawater intrusion using chloride concentrations, or other measurements convertible to chloride concentrations, so that the current and projected rate and extent of seawater intrusion for each applicable principal aquifer may be calculated. 7.1.3
(4)
Degraded Water Quality. Collect sufficient spatial and temporal data from each applicable principal aquifer to determine groundwater quality trends for water quality indicators, as determined by the Agency, to address known water quality issues. 7.1.5 Figure 7-2 Table 7-2 (5)
Land Subsidence. Identify the rate and extent of land subsidence, which may be measured by extensometers, surveying, remote sensing technology, or other appropriate method. 7.1.4
(6)
Depletions of Interconnected Surface Water. Monitor surface water and groundwater, where interconnected surface water conditions exist, to characterize the spatial and temporal exchanges between surface water and groundwater, and to calibrate and apply the tools and methods necessary to calculate depletions of surface water caused by groundwater extractions. The monitoring network shall be able to characterize the following:
(A) Flow conditions including surface water discharge, surface water head, and baseflow contribution. 7.1.6
(B) Identifying the approximate date and location where ephemeral or intermittent flowing streams and rivers cease to flow, if applicable. 7.1.6
(C) Temporal change in conditions due to variations in stream discharge and regional groundwater extraction. 7.1.6
(D) Other factors that may be necessary to identify adverse impacts on beneficial uses of the surface water. 7.1.6
(d)
The monitoring network shall be designed to ensure adequate coverage of sustainability indicators. If management areas are established, the quantity and density of monitoring sites in those areas shall be sufficient to evaluate conditions of the basin setting and sustainable management criteria specific to that area. 7.1 Figure 7-1
and 7-2
(e) A Plan may utilize site information and monitoring data from existing sources as part of the monitoring network. 7.1 Table 7-1

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(f)
The Agency shall determine the density of monitoring sites and frequency of measurements required to demonstrate short-term, seasonal, and long-term trends based upon the following factors:
(1) Amount of current and projected groundwater use. 7.1 (2) Aquifer characteristics, including confined or unconfined aquifer conditions, or other physical characteristics that affect groundwater flow. 7.1 (3)
Impacts to beneficial uses and users of groundwater and land uses and property interests affected by groundwater production, and adjacent basins that could affect the ability of that basin to meet the sustainability goal. 7.1 (4) Whether the Agency has adequate long-term existing monitoring results or other technical information to demonstrate an understanding of aquifer response. 7.1 (g) Each Plan shall describe the following information about the monitoring network:
(1) Scientific rationale for the monitoring site selection process. 7.1 (2)
Consistency with data and reporting standards described in Section 352.4. If a site is not consistent with those standards, the Plan shall explain the necessity of the site to the monitoring network, and how any variation from the standards will not affect the usefulness of the results obtained. 7.2
(3)
For each sustainability indicator, the quantitative values for the minimum threshold, measurable objective, and interim milestones that will be measured at each monitoring site or representative monitoring sites established pursuant to Section 354.36. 7.1 (h)
The 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. 7.1
(i)
The monitoring protocols developed by each Agency shall include a description of technical standards, data collection methods, and other procedures or protocols pursuant to Water Code Section 10727.2(f) for monitoring sites or other data collection facilities to ensure that the monitoring network utilizes comparable data and methodologies. 7.2
(j)
An Agency that has demonstrated that undesirable results related to one or more sustainability indicators are not present and are not likely to occur in a basin, as described in Section 354.26, shall not be required to establish a monitoring network related to those sustainability indicators. 7.1
Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10723.2, 10727.2, 10727.4, 10728, 10733, 10733.2, and 10733.8, Water Code
§ 354.36. Representative Monitoring
Each Agency may designate a subset of monitoring sites as representative of conditions in the basin or an area of the basin, as follows:
(a)
Representative monitoring sites may be designated by the Agency as the point at which sustainability indicators are monitored, and for which quantitative values for minimum thresholds, measurable objectives, and interim milestones are defined. 7.3

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(b) (b) Groundwater elevations may be used as a proxy for monitoring other sustainability indicators if the Agency demonstrates the following:
(1) Significant correlation exists between groundwater elevations and the sustainability indicators for which groundwater elevation measurements serve as a proxy. 7.3 (2)
Measurable objectives established for groundwater elevation shall include a reasonable margin of operational flexibility taking into consideration the basin setting to avoid undesirable results for the sustainability indicators for which groundwater elevation measurements serve as a proxy. 7.3
(c) The designation of a representative monitoring site shall be supported by adequate evidence demonstrating that the site reflects general conditions in the area. 7.3 Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10727.2 and 10733.2, Water Code
§ 354.38. Assessment and Improvement of Monitoring Network (a)
Each Agency shall review the monitoring network and include an evaluation in the Plan and each five-year assessment, including a determination of uncertainty and whether there are data gaps that could affect the ability of the Plan to achieve the sustainability goal for the basin. 7.5 Table 7-3
(b)
Each Agency shall identify data gaps wherever the basin does not contain a sufficient number of monitoring sites, does not monitor sites at a sufficient frequency, or utilizes monitoring sites that are unreliable, including those that do not satisfy minimum standards of the monitoring network adopted by the Agency. 7.5 Table 7-3 (c) If the monitoring network contains data gaps, the Plan shall include a description of the following:
(1) The location and reason for data gaps in the monitoring network. Table 7-3 (2) Local issues and circumstances that limit or prevent monitoring. 7.5 Table 7-3 (d)
Each Agency shall describe steps that will be taken to fill data gaps before the next fiveyear assessment, including the location and purpose of newly added or installed monitoring sites. 7.5 Table 7-3
(e)
Each Agency shall adjust the monitoring frequency and density of monitoring sites to provide an adequate level of detail about site-specific surface water and groundwater conditions and to assess the effectiveness of management actions under circumstances that include the following:
(1) Minimum threshold exceedances. 7.1
(2) Highly variable spatial or temporal conditions. 7.1 (3) Adverse impacts to beneficial uses and users of groundwater. 7.1 (4) The potential to adversely affect the ability of an adjacent basin to implement its Plan or impede achievement of sustainability goals in an adjacent basin. 7.1 Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10723.2, 10727.2, 10728.2, 10733, 10733.2, and 10733.8, Water Code
§ 354.40. Reporting Monitoring Data to the Department

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Monitoring data shall be stored in the data management system developed pursuant to Section 352.6. A copy of the monitoring data shall be included in the Annual Report and submitted electronically on forms provided by the Department.

Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10728, 10728.2, 10733.2, and 10733.8, Water Code.

SubArticle 5. Projects and Management Actions
§ 354.42. Introduction to Projects and Management Actions This Subarticle describes the criteria for projects and management actions to be included in a Plan to meet the sustainability goal for the basin in a manner that can be maintained over the planning and implementation horizon.

Note: Authority cited: Section 10733.2, Water Code.

Reference: Section 10733.2, Water Code.
§ 354.44. Projects and Management Actions
(a)
Each Plan shall include a description of the projects and management actions the Agency has determined will achieve the sustainability goal for the basin, including projects and management actions to respond to changing conditions in the basin. 8 (b) Each Plan shall include a description of the projects and management actions that include the following:
(1)
A list of projects and management actions proposed in the Plan with a description of the measurable objective that is expected to benefit from the project or management action. The list shall include projects and management actions that may be utilized to meet interim milestones, the exceedance of minimum thresholds, or where undesirable results have occurred or are imminent. The Plan shall include the following:
(A)
A description of the circumstances under which projects or management actions shall be implemented, the criteria that would trigger implementation and termination of projects or management actions, and the process by which the Agency shall determine that conditions requiring the implementation of particular projects or management actions have occurred. 8.1,8.2,8.3
Tables 8-1
through 8-
4 (B)
The process by which the Agency shall provide notice to the public and other agencies that the implementation of projects or management actions is being considered or has been implemented, including a description of the actions to be taken. 8.1,8.2,8.3 Tables 8-1
through 8-
4 (2)
If overdraft conditions are identified through the analysis required by Section 354.18, the Plan shall describe projects or management actions, including a quantification of demand reduction or other methods, for the mitigation of overdraft. NA (3) A summary of the permitting and regulatory process required for each project and management action. 8.1,8.2,8.3
Tables 8-1
through 8-
4

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(4) The status of each project and management action, including a time-table for expected initiation and completion, and the accrual of expected benefits. 8.1,8.2,8.3 Tables 8-1
through 8-
4 (5) An explanation of the benefits that are expected to be realized from the project or management action, and how those benefits will be evaluated. 8.1,8.2,8.3 Tables 8-1
through 8-
4 (6)
An explanation of 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. 8.1,8.2,8.3 Tables 8-1
through 8-
4 (7) A description of the legal authority required for each project and management action, and the basis for that authority within the Agency. 8.1,8.2,8.3 Tables 8-1
through 8-
4 (8) A description of the estimated cost for each project and management action and a description of how the Agency plans to meet those costs. 8.1,8.2,8.3 Tables 8-1
through 8-
4 (9)
A description of the management of groundwater extractions and recharge to ensure that chronic lowering of groundwater levels or depletion of supply during periods of drought is offset by increases in groundwater levels or storage during other periods. 8.1,8.2,8.3 Tables 8-1
through 8-
4 (c) Projects and management actions shall be supported by best available information and best available science. 8.1,8.2,8.3
Tables 8-1
through 8-
4 (d) An Agency shall take into account the level of uncertainty associated with the basin setting when developing projects or management actions. 8.1,8.2,8.3 Tables 8-1
through 8-
4 Note: Authority cited: Section 10733.2, Water Code.

Reference: Sections 10727.2, 10727.4, and 10733.2, Water Code.

Temescal Basin GSP

APPENDIX D
Temescal Groundwater Sustainability Plan
Stakeholder Outreach Plan

Temescal Subbasin Groundwater Sustainability Plan
Outreach and Stakeholder Involvement
Communications Plan
July 22, 2020
__________________________________________________________ Prepared for:

City of Corona Department of Water and Power
Prepared by:

Kearns & West, in coordination with Todd Groundwater

Table of Contents

1. Introduction..................................................................................................................................................................1 Background...................................................................................................................................................................1 Purpose ..........................................................................................................................................................................2 Objectives......................................................................................................................................................................2 A Note on Covid-19...................................................................................................................................................2

2. GSA Decision Making Process...............................................................................................................................3

3. Stakeholders and Potential Interests ..................................................................................................................4 List of Interested Parties ..........................................................................................................................................4 Stakeholder Categories ............................................................................................................................................4 Disadvantaged and Severely Disadvantaged Communities.......................................................................4 Potential Stakeholder Interests .............................................................................................................................5

4. Steps for Preparation of the Groundwater Sustainability Plan .................................................................6

5. Outreach and Involvement Process.....................................................................................................................7 Outreach and Involvement Activities ..................................................................................................................8 Groundwater Sustainability Plan Webpage .................................................................................................8 Pre-Workshop Outreach .....................................................................................................................................8 Focused Outreach..................................................................................................................................................9 Technical Advisory Committee Meetings .....................................................................................................9 Public Workshops ............................................................................................................................................... 10 City Council and Board of Directors Meeting Presentations.............................................................. 10 Public Comment Period.................................................................................................................................... 11 Inter-basin Coordination.................................................................................................................................. 11

6. Evaluation and Adaptation .................................................................................................................................. 11 Appendices
A – Temescal Subbasin Map
B – List of Interested Parties
C – Disadvantaged and Severely Disadvantaged Communities Map D – Technical Advisory Committee Protocols and Operating Principals

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1. Introduction
Background
The State of California Sustainable Groundwater Management Act (SGMA), passed in 2014, calls for the development and implementation of groundwater sustainability plans for all basins determined high and medium priority by the California Department of Water Resources. Under SGMA, these basins should reach sustainability within 20 years of implementing their sustainability plans with a deadline of 2042. SGMA gives local agencies authority to define and plan for achieving and maintaining sustainable groundwater management while avoiding specific undesirable results through the preparation and implementation of a Groundwater Sustainability Plan (GSP).

The Temescal Subbasin is designated as a medium-priority basin. The basin lies mostly within the boundaries of the cities of Corona and Norco, and Home Gardens, an unincorporated area of Riverside County within the City of Corona’s sphere of influence. See Appendix A for the Temescal Subbasin map. The City of Corona Department of Water and Power, the City of Norco, and Home Gardens County Water District provide water service to most of the basin, but there are some small areas outside the agencies’ combined jurisdictions. These areas are either managed by the U.S. Forest Service, or underlie Prado Reservoir, which is operated by the United States Army Corps of Engineers.

Public agencies with water or land use authority are eligible to sustainably manage groundwater resources locally through the formation of a Groundwater Sustainability Agency (GSA) and preparation of a GSP. The Temescal Subbasin GSA (hereafter GSA) was formed by a Memorandum of Understanding (MOU) among the City of Corona, the City of Norco, and the Home Gardens County Water District. The GSA is dedicated to participating in the collective goals of groundwater sustainability and good basin management through the development of a GSP for the Temescal Subbasin.

Sustainable management of the Temescal Subbasin is critical to local water supply reliability. The three local agencies have water supply portfolios that include imported water, groundwater from multiple local basins, and Corona and Norco use reclaimed water for landscape irrigation.

Water conservation measures have also been implemented (as documented in the recent Corona and Norco Urban Water Management Plans) and provide an important tool for responding to water shortages.

The GSA members have long cooperated in water supply planning, monitoring, and management in the Temescal Subbasin. The City of Corona has had a lead role, including preparation in 2008 of a Groundwater Management Plan for the Temescal Subbasin in accordance with State Assembly Bill 3030. This cooperative management will continue for preparation of the Temescal Subbasin GSP (hereafter GSP). The GSP will be prepared and applied jointly among the three agencies. Under the MOU establishing the GSA, the City of

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 2 Corona accepted the lead role in developing a GSP for the Temescal Subbasin and submitting it to the California Department of Water Resources.

Purpose
The purpose of this Outreach and Stakeholder Involvement Communications Plan is to provide a framework for integrating public and stakeholder outreach and involvement into GSP preparation. The Outreach and Stakeholder Involvement Communications Plan clarifies objectives, outlines important categories of stakeholders and potential interests, determines methods and timing of outreach and involvement activities, and establishes a process for evaluation and adaptation should the plan need to be updated. Under the requirements of SGMA, GSAs must consider the interests of all beneficial uses and users of groundwater and provide opportunities for public engagement and active involvement of diverse social, cultural, and economic elements of the population.

Objectives
This plan will help ensure SGMA requirements are met for the unique needs of the communities and stakeholders connected to the groundwater of the Temescal Subbasin. The plan will also be guided by the additional stakeholder outreach and stakeholder involvement objectives determined by the GSA. These objectives are to:
• Inform all stakeholders of the GSP development process, including purpose, opportunities and issues, core recommendations, and timeline. • Provide meaningful opportunities for stakeholders and the public to learn, ask questions, and provide input.
• Involve the many diverse communities and stakeholders of Corona, Norco, and Home Gardens, recognizing that different approaches may be needed to reach specific populations like Disadvantaged Communities, and flexibility and adaptation in approach may be required.
• Ensure a transparent process where stakeholders and the public can understand what important discussions are taking place, how they can participate in them, and how input is being used.

A Note on Covid-19
Given the current Covid-19 crisis, many activities that would usually take place in-person during a planning process, such as workshops and community events, may not be possible. With the uncertainty of when in-person activities will be allowed by local and state authorities or deemed safe by communities, other involvement tools like virtual public meetings and communication and calls with partners will be employed where appropriate to meet the involvement goals for the GSP. Furthermore, even when in-person gatherings are allowed by health authorities, there may be community members who are not able to attend due to individual risk factors. Weaving different virtual activities together with the GSP process will require flexibility as well as thoughtfulness in involving the public.

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2. GSA Decision Making Process
As noted, the cities of Corona and Norco and the Home Gardens County Water District have developed and adopted an MOU forming the GSA for the Temescal Subbasin. The GSP will be prepared under the authority of the GSA, with the City of Corona serving as lead agency.

The City of Corona is a General Law City operating with a City Council/City Manager form of government. The City Council is composed of five Council Members including the Mayor and Vice Mayor. Corona's City Council Members are community leaders who listen to all citizens of the City, prioritize plans and projects, allocate funds, and make decisions essential to the future of Corona. The Corona City Council members are elected officers identified in Government Code Section 87200. The City Council meets the first and third Wednesday of each month at 6:30 PM at Corona City Hall, 400 South Vicentia Ave, Corona, California. Meetings are announced, and agenda are posted on the City of Corona website; the meetings are open to the public. The vote of a majority of City Council Members present at any meeting attended by a quorum is necessary to determine any proposition or resolution presented. The City Council is supported by City staff from multiple departments. The Department of Water and Power is leading the GSP work for the City and other members of the GSA.

The City of Norco is a Charter City operating with a City Council/City Manager form of government. The Norco City Council is the elected body of city government within the City of Norco. The Norco City Council consists of five members elected at large for four-year terms by the citizens of Norco. Annually, the Norco City Council appoints a Mayor and Mayor Pro-Tem from its own membership to serve a one-year term. The Norco City Council makes all policy decisions and adopts laws for the City of Norco. The Norco City Council members are elected officers identified in Government Code Section 87200. The City Council meets the first and third Wednesday of each month at 7:00 p.m. at Council Chambers located at 2820 Clark Avenue, Norco, California. Meetings are announced and open to the public. The vote of a majority of City Council Members present at any meeting attended by a quorum is necessary to determine any proposition or resolution presented. Norco City Council meeting agenda are posted on the City of Norco website.

The Home Gardens County Water District is a special district formed under State law to provide water supply within its service area. Home Gardens is governed by a 5-person Board of Directors that elects a president from its members and appoints a secretary. The Board meets every 3rd Thursday of every month at its office, located at 3832 Grant St, Corona, California. Meetings are announced, and agenda are posted at various public locations throughout Home Gardens; the meetings are open to the public. The board (except as otherwise specifically provided in the California Water Code) manages and conducts the business and affairs of the Home Gardens County Water District. The vote of a majority of directors present at any meeting attended by a quorum is necessary to determine any proposition or resolution presented.

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3. Stakeholders and Potential Interests
List of Interested Parties
Formulating an effective GSP will rely in part on soliciting input from as many stakeholders as possible to ensure that the plan explores and addresses the topics of greatest interest. During formation, the GSA submitted an initial list of parties interested in receiving notices regarding plan preparation, meeting announcements, and availability of draft plans, maps, and other relevant documents (see Appendix B). This initial list was used to create a list of stakeholders that will be updated throughout the GSP preparation.

Stakeholder Categories
Community members and contacts from stakeholder organizations (such as local, state, and federal agencies; businesses; community organizations; and non-profits) will be sought and involved throughout GSP preparation. The following are key stakeholder categories:
• Agricultural Interests
• California Native American Tribes
• California Statewide Groundwater Elevation Monitoring Agencies • Businesses and Development
• Disadvantaged Communities
• Domestic Well Owners
• Environmental and Conservation
• Extractive Industry
• Federal Government Agencies
• Groundwater Right Holders
• Industrial Well Operators
• Land Use Planning Agencies
• Local Water Districts
• Municipal Well Operators
• Private Water Users
• Regulatory Agencies
• Surface Water User
Disadvantaged and Severely Disadvantaged Communities
Disadvantaged Communities are characterized by an annual median household income less than 80% of the California statewide median household income and Severely Disadvantaged Communities are characterized by an annual median household income less than 60% of the California statewide median household income. In many instances, members of these communities have faced historical disinvestment, systemic racism, and environmental injustices among other systemic challenges. Focused attention is required to ensure that they are provided opportunities to be informed and involved in planning processes.

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 5 The map in Appendix C shows the Disadvantaged and Severely Disadvantaged Communities within the Temescal Subbasin, representing all the areas identified from census-designated places, tracts, and block groups. The map reveals broad disadvantaged areas across the communities of the City of Corona and Home Gardens, centered around the State Route 91 corridor stretching from both sides of its intersection with Interstate 15 to State Route 71, including areas near the Corona Municipal Airport. As noted in the One Water One Watershed Plan Update 2018 (the Integrated Regional Water Management Plan for the Santa Ana River Watershed), specific communities who meet the criteria for disadvantaged communities may need to be involved, but are not yet identifiable by currently available census information. These communities will be included in focused outreach as they are identified. Involving these communities is needed for the preparation and implementation of the GSP in a way that supports a long‐term sustainable water supply while reducing cost burdens.

Several of the identified areas score in the 70th to 80th percentiles for linguistic isolation on CalEnviroScreen, indicating that many households have low levels of English proficiency.

American Community Survey data indicates Spanish as the most commonly spoken language other than English in Corona, Home Gardens, and Norco. The communities near the center of the City of Corona contain many single-family residences near commercial areas. Away from the center of Corona, including Home Gardens, the neighborhoods contain higher density residential and more mixed use and industrial areas. These factors are important to consider while developing focused outreach and involvement. For example, outreach material language translation will likely be needed in areas with limited English proficiency. Multiple means of communication (e.g., flyers, posters) will be utilized, recognizing that some communication methods directed toward rate payers (e.g., water bill insert) might not reach community members in multi-unit buildings if water is included in their rent. See the “Focused Outreach” subsection in Section 4 for more details on strategy.

Potential Stakeholder Interests
When planning for public outreach and stakeholder involvement, it is important to consider the types of questions and concerns stakeholders and the public may have. To help guide involvement efforts, a list of potential stakeholders and example interests is presented below in Table 1.

Table 1 – Potential Stakeholder Interests
Category Example Interests
Agriculture • Crop prices
• Groundwater production and use costs
• Water supply availability
• Water rights
• Water quality
• Land value
Business and Development • Economic growth
• Population growth

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 6 Table 1 – Potential Stakeholder Interests
Category Example Interests
• Water rates
• Water quality
Cultural Resources • Community history
• Cultural identity
Environment and Conservation • Climate change
• Groundwater dependent ecosystems
• Habitat and species of concern
• Managed/preserved land
• Water quality
Equity and Environmental Justice • Access to planning process • Benefits to disadvantaged communities
• Greater exposure to air, land, and water
contaminants
• Water quality
• Water rates
Water Suppliers • Drought
• Groundwater supply availability
• Groundwater production and use costs
• Potential future limits on groundwater
pumping
• Water quality

4. Steps for Preparation of the Groundwater Sustainability Plan
Activities for this Outreach and Stakeholder Involvement Communications Plan will take place during six steps of preparation for the GSP. The steps are outlined below with brief descriptions of the key activities in each step.
• Step 1: Launch Project. During project launch, the project team will organize itself for the GSP preparation and stakeholder outreach and involvement. Project planning and project management structures will be established.
• Step 2: Conduct Baseline Studies. In this step, describing the plan area and conducting baseline studies for the planning process will occur. This includes describing current and historical groundwater conditions and developing the hydrogeologic conceptual model, which describes the occurrence and movement of groundwater in the Temescal Subbasin.
• Step 3: Build Water Budget and Numerical Model. At this step, the water budget will be quantified, which describes the amount of water that flows in and out of the subbasin, estimates changes in the amount of stored groundwater, and discusses the annual sustainable yield of the subbasin. A numerical groundwater model of the subbasin will be built in this step to assist in groundwater budget quantification. The model will be used

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 7 to evaluate future sustainability in multiple scenarios (including projected growth and climate change) and to simulate potential projects and management actions. • Step 4: Define Sustainability Goal and Criteria. Building from the baseline studies, water budget, modeling, and input of stakeholders in the previous steps, the activities of this step will define the unique sustainability goal for the Temescal Subbasin. This goal and associated sustainable management criteria will define undesirable results and identify thresholds to avoid significant and unreasonable lowering of groundwater levels, reduction in storage, degraded water quality, land subsidence, and surface water depletion in the subbasin.
• Step 5: Prepare Draft GSP. This step will identify monitoring and management actions to fulfill the sustainability goal and sustainable management criteria and provide a plan for GSP implementation. The technical contents of the Draft GSP will then be completed. • Step 6: Review Draft GSP and Adopt Final GSP. In the final step, the draft and final plan will be distributed for public review and comment.

See Section 4 for a process chart that aligns these planning steps with outreach and involvement activities.

5. Outreach and Involvement Process
The process chart on the next page provides an overview of how stakeholder and public outreach, and involvement activities align with the GSP preparation steps described in Section 3.

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 7

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 8 Outreach and Involvement Activities
Listed below are the anticipated stakeholder and public involvement activities that will occur during GSP preparation. They are listed in the order of appearance in the above process chart.

The activities are designed to be flexible to meet evolving needs and issues during GSP preparation. Detailed logistics plans will be prepared prior to public workshops and technical advisory committee meetings, and will outline notification methods, formats, key messages, topics, and input and feedback opportunities.

Groundwater Sustainability Plan Webpage
Purpose: Host information about GSP preparation and related involvement activities.

Description: A webpage will be created on the City of Corona Department of Water and Power’s website. It will host project information such as general SGMA/GSP information, project timeline, draft chapters, project updates, meeting materials and summaries, and FAQs. It will also allow visitors to sign up for the interested parties list.

Timing: All Steps.

Pre-Workshop Outreach
Purpose: Inform stakeholders about GSP preparation and drive attendance at public workshops.

Description: Pre-workshop outreach will use outreach materials and social media materials.

Outreach Materials
Potential outreach materials include one-page fact sheets (or similar materials such as project updates or notices) or bill insert announcements. The materials will be posted on the webpage, distributed to the interested parties list via email, and to the public using social media and community organizations. The timing of the creation and distribution of outreach materials will be tied to project milestones and public workshops.

Social Media, Websites, and Email
The GSA members will utilize their existing social media accounts to spread the word following completion of project milestones and in advance of public workshops. Posts on the City of Corona’s Facebook, Twitter, Instagram, and/or Nextdoor pages will distribute information, outreach materials, and/or direct interested parties to the GSP webpage and public workshops. The City of Corona’s Inner Circle email distribution list will likewise be used to disseminate information. The City of Norco will distribute information using its Facebook and Twitter accounts. Home Gardens County Water District has a webpage where workshop information will be posted. Stakeholder organizations will be encouraged to repost social media communications for wider distribution.

Timing: Step 2, Conduct Baseline Studies; Step 4, Define Sustainability Goal and Criteria; Step 5, Prepare Draft GSP; Step 6, Review Draft GSP and Adopt Draft GSP

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 9 Focused Outreach
Purpose: Involve Disadvantaged Communities and Severely Disadvantaged Communities.

Description: Throughout GSP preparation, opportunities will be for outreach to Disadvantaged and Severely Disadvantaged Communities. In Step 1, the foundation will be laid by reaching out to community leaders and organizations to begin to build relationships and learn what strategies have been successful for them, how to overcome any existing barriers, and best methods for engaging in culturally and linguistically appropriate ways. Using this information and the previously discussed demographic information, gaps in pre-workshop outreach methods will be identified and addressed. Spanish translation of materials and interpretation at events will also be woven into outreach and involvement. Examples of effective outreach that has already been identified include posts on community social media pages and receiving information in the mail. Potential outreach materials could include customized social media posts for community organizations to share.

In Step 2, focused outreach, such as virtual stakeholder meetings, social media livestreams, social media posts, or flyer distribution, will be conducted, possibly in partnership with community groups and leaders. The purpose is to inform community members of their groundwater resources, how they are managed, and who manages them so that they are more comfortable in engaging in discussions later in GSP preparation. Basic information about the role of the GSP in groundwater management and public involvement will also be introduced.

Potential outreach materials could include stakeholder meeting presentations, social media posts, or informational flyers.

Steps 3-6 will include continuation of pre-workshop outreach methods. It is also possible that some community members in disadvantaged communities may not have easy access to internet or cell phone data, so in-person meetings may be considered, if allowed by health authorities and community members are not excluded from public gatherings due to vulnerability to infection.

Timing: All Steps.

Technical Advisory Committee Meetings
Purpose: The purpose of the Technical Advisory Committee (TAC) is to contribute community and stakeholder perspectives and interests in GSP planning and GSP and SGMA implementation in the Temescal Subbasin.

Description: TAC members will provide input and feedback on GSP development and implementation and GSA policies based on their expertise, knowledge, resources, and understanding of their communities, environment, commerce, and applicable regulations. The GSA and the project team will consider the TAC’s input throughout GSP preparation, along with input from the broader community, other stakeholders, and other government agencies involved in groundwater management and associated regulatory requirements.

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 10 TAC members represent the diverse interests of GSA-eligible agencies and groundwater uses and users. The intent of the Technical Advisory Committee is to contribute community and stakeholder perspectives and interests in GSP planning and GSP and SGMA implementation in the Temescal Subbasin.

See Appendix D for the protocols and operating principals document.

Timing: Step 2, Conduct Baseline Studies; Step 3, Build Water Budget and Numerical Model; Step 4, Define Sustainability Goal and Criteria; Step 5, Prepare Draft GSP.

Public Workshops
Purpose: Create a forum to share project information with the public and stakeholders and provide input and feedback opportunities.

Description: Public workshops will allow stakeholders an opportunity to provide incremental input at meaningful points in GSP development. The workshop series will also help community members and other stakeholders understand the purpose, need, benefits, and issues associated with sustainable groundwater planning. The planned focus of these workshops is the following:

1. Kickoff (Step 2, Conduct Baseline Studies)

2. Criteria for sustainability (Step 4, Define Sustainability Goal and Criteria)

3. Preliminary evaluation of management actions (Step 5, Prepare Draft GSP)

4. Presentation of draft GSP (Step 6, Review Draft GSP and Adopt Draft GSP) Public workshops could include elements such as a presentation, Q&A sessions, and various opportunities for attendees to provide input or feedback such as live polling, breakout groups, or comment cards. The first public workshop will likely take the form of a virtual meeting. The project team will assess the conditions for future workshops and weigh the risks and benefits of holding them in-person. Any in-person workshops will be held in a venue that maximizes accessibility and convenience for the communities of Corona, Home Gardens, and Norco.

Timing: Step 2, Conduct Baseline Studies; Step 3, Build Water Budget and Numerical Model; Step 4, Define Sustainability Goal and Criteria; Step 5, Prepare Draft GSP; Step 6, Review Draft GSP and Adopt Draft GSP
City Council and Board of Directors Meeting Presentations Purpose: Update the city councils of the Cities of Corona and Norco, and the Board of Directors of Home Gardens, and their respective communities, on GSP development and hold the GSP adoption hearing.

Description: The public will be able to hear updates on GSP preparation as an agenda item and provide comment periodically throughout the planning process and at the final adoption hearing.

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 11 Timing: Step 2, Conduct Baseline Studies; Step 3, Step 4, Define Sustainability Goal and Criteria; Step 5, Prepare Draft GSP; Step 6, Review Draft GSP and Adopt Draft GSP Public Comment Period
Purpose: Allow the public to comment on the GSP before adoption.

Description: According to SGMA, a GSA may adopt a GSP after a public hearing, held at least 90 days after providing public notice of a comment period. Draft GSP materials, including draft chapters and supporting documents will also be released for public review periodically throughout GSP preparation to facilitate additional public review.

Timing: Step 2, Conduct Baseline Studies; Step 3, Step 4, Define Sustainability Goal and Criteria; Step 5, Prepare Draft GSP; Step 6, Review Draft GSP and Adopt Draft GSP Inter-basin Coordination
Purpose: SGMA requires coordination of specific GSP elements between connected basins and/or subbasins.

Description: The GSA and their technical consultants will communicate with the GSAs, agencies, and/or technical consultants in and for neighboring basins and subbasins to coordinate water budget and sustainability criteria. This will facilitate consistency in estimates of flow across basin boundaries and make sure that sustainable basin management does not adversely affect neighboring basins.

Timing: Step 2, Conduct Baseline Studies; Step 3, Step 4, Define Sustainability Goal and Criteria; Step 5, Prepare Draft GSP; Step 6, Review Draft GSP and Adopt Draft GSP

6. Evaluation and Adaptation
This is a working plan, recognizing that an outreach and involvement plan should allow for evaluation and adaptation. After each public workshop, a discussion and evaluation of outreach and involvement activities will occur at internal GSA workgroup meetings to determine what went well, what could be improved, and what the key lessons learned are.

To help answer those questions, the outreach and involvement plan objectives will be reviewed:
• Were all stakeholders informed of the GSP development process, including purpose, opportunities and issues, core recommendations, and timeline? • Were stakeholders and the public provided meaningful opportunities to learn, ask questions, and provide input?
• Were the many diverse communities and stakeholders of Corona, Norco, and Home Gardens, involved? Were tailored approaches used to reach specific populations like Disadvantaged Communities?

Temescal Subbasin GSP | Outreach and Stakeholder Involvement Communications Plan 12 • Was the process transparent such that stakeholders and the public can understand what important discussions are taking place, how they can participate in them, and how input is being used ensured?
The following information can also be collected and used as indicators:
• Interested Party List Additions: Number of contacts added to the list since the last workshop.
• Social Media Interactions: Number of likes, comments, and shares. • Public Workshops Attendance: Number of attendees and change over time. • Public Workshop Feedback: Public workshops will end with a poll and/or short survey, asking attendees how they learned about the workshop, recommending means for getting the word out to other community members, what they liked about the format, and what they liked least.

The evaluation input will inform the adaptation of subsequent outreach and involvement activities.

Appendix A
Temescal Subbasin Map

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Temescal Canyon Road
City of Corona
Service Area
City of Norco
Service Area
Home Gardens
County Water District
Service Area Temescal
Subbasin
(8-002 .09)
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Temescal Subbasin Groundwater Sustainability Agency (GSA) City of Corona Service Area
City of Norco Service Area
Home Gardens County Water District Service Area
Temescal Subbasin of the Upper Santa Ana Valley Groundwater Basin Exhibit A
Temescal Subbasin
Groundwater
Sustainability Agency
0 0.5 1
Miles
(
N

Appendix B
List of Interested Parties

TEMESCAL VALLEY SUBBASIN

GROUNDWATER SUSTAINABILITY AGENCY

LIST OF PARTIES INTERESTED IN THE TEMESCAL SUBBASIN
The following list satisfies Water Code Section 10723.2, which states: a GSA shall consider the interests of all beneficial uses and users of groundwater, as well as those responsible for implementing Groundwater Sustainability Plans (GSPs). The list of interested parties presented below has been developed for the GSA. Many of the agencies identified below have already been contacted by the parties to the MOU for the GSA. The interests of all the agencies, organizations, and individuals identified below shall be considered during the development of the GSP for the GSA.

1. Local Water Districts within or adjoining the GSA:
a. Metropolitan Water District of Southern California
b. City of Riverside
c. The MOU/GSA member agencies
d. Western Municipal Water District (adjacent to the subbasin/GSA) e. City of Eastvale (adjacent)
f. City of Chino Hills (adjacent)
g. Jurupa Community Services District (adjacent)
h. Temescal Valley Water District (adjacent)
i. Eagle Valley Water District (adjacent)
j. Orange County Water District (adjacent)
k. Orange County Water Public Works Department (adjacent) l. Inland Empire Utilities Agency (adjacent)
m. Chino Basin Water Management District (adjacent)

2. Holders of Overlying Groundwater Rights:
a. There are a limited number of known agricultural, industrial, and domestic well owners that account for a very small proportion of subbasin annual groundwater use. These existing pumpers include the Dairy Farmers of America and other small producers. Known pumping is tracked on behalf of the Santa Ana River Watermaster, and these producers interests will be considered during the development of the GSP for the subbasin. b. Municipal and Industrial Well Operators
i. The MOU/GSA member agencies are the only municipal well operators within the Temescal Subbasin
ii. All American Asphalt, Dart Container Corporation of California, and Minnesota Mining and Manufacturing Corporation operate
industrial supply wells in the subbasin. Known pumping is tracked on behalf of the Santa Ana River Watermaster, and these producers interests will be considered during the development of the GSP for the subbasin.

3. Surface Water Users
a. Santa Ana Watershed Protection Authority
b. Santa Ana River Watermaster. The Santa Ana River overlies portions of the Basin. Surface flows in the Santa Ana River are monitored by the Santa Ana River Watermaster. The Santa Ana River is adjudicated and minimum flows are required to reach the Prado Basin on an annual basis. c. The MOU/GSA member agencies

4. Environmental Users of Groundwater
a. Riverside County Flood Control and Water Conservation District b. Santa Ana River Watermaster
c. California Regional Water Quality Control Board - Santa Ana Region (8)

5. Local Land Use Planning Agencies
a. Riverside County, Planning Department
b. City of Corona
c. City of Norco

6. The Federal Government
a. United States Army Corps of Engineers (Prado Dam Management Area) b. United States Forest Service

7. California Native American Tribes
a. Not present within the Temescal Subbasin or proposed GSA area.

8. Disadvantaged Communities
a. There are 21 Census block groups within the City of Corona where median income is below the threshold for disadvantaged communities, and 13 of these block groups are below the severely disadvantaged community income threshold.
b. There are 4 Census block groups within the Home Gardens County Water District where median income is below the threshold for severely disadvantaged communities.

9. CASGEM Agencies
a. Western Municipal Water District is the monitoring entity responsible for CASGEM program in the Temescal Subbasin

Appendix C
Disadvantaged and Severely
Disadvantaged Communities Map

November 2017 Disadvantaged and
Severely Disadvantaged
Community Block Groups
Temescal Subbasin
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Disadvantaged Community
Severely Disadvantaged Community
Temescal Subbasin
(
N
0 3,000 6,000
Scale in Feet
C-1

Appendix D
Protocol and Operating Principles
for Temescal GSA Technical
Advisory Commitee

1 Protocols and Operating Principles for
Temescal Subbasin
Groundwater Sustainability Agency
Technical Advisory Committee
August 7, 2020

1. INTRODUCTION
The State of California Sustainable Groundwater Management Act (SGMA), passed in 2014, calls for the development and implementation of groundwater sustainability plans for all basins determined high and medium priority by the California Department of Water Resources. Under SGMA, these basins should reach sustainability within 20 years of implementing their sustainability plans with a deadline of 2042. SGMA gives local agencies authority to define and plan for achieving and maintaining sustainable groundwater management while avoiding specific undesirable results through the preparation and implementation of a Groundwater Sustainability Plan (GSP).

The Temescal Subbasin, a medium-priority basin, lies mostly within the boundaries of the cities of Corona and Norco, and Home Gardens, an unincorporated area of Riverside County within the City of Corona’s sphere of influence. The Temescal Subbasin GSA (GSA) was formed by a Memorandum of Understanding among the City of Corona, the City of Norco, and the Home Gardens County Water District. The GSA is dedicated to participating in the collective goals of groundwater sustainability and good basin management through the development of a GSP for the Temescal Subbasin.

GSAs must consider the interests of all beneficial uses and users of groundwater and provide opportunities for public engagement and the Temescal Subbasin GSA is seeking active involvement of diverse social, cultural, and economic elements of the population. In order to achieve those requirements and provide more opportunities for stakeholders to represent diverse interests and provide input to inform GSP preparation, the GSA chose to form a Technical Advisory Committee (TAC). This document establishes the protocols and operating principles and records the charge and role of the TAC in GSP preparation, collaborative principles, meeting logistics information, and additional considerations for productive meetings where all TAC members can participate equally and effectively.

2 2. CHARGE
The purpose of the TAC is to provide input and guidance to the staff and consultant team of the GSA who are preparing the GSP. At the request of the GSA, the TAC members will provide input and feedback on GSP development and implementation and GSA policies based on their expertise, knowledge, resources, and understanding of their communities, environment, commerce, and applicable regulations. The GSA and the project team will consider the TAC’s input throughout GSP preparation, along with input from the broader community, other stakeholders, and other government agencies involved in groundwater management and associated regulatory requirements.

Additionally, Technical Advisory Committee members represent the diverse interests of GSAeligible agencies and groundwater uses and users. The intent of the Technical Advisory Committee is to contribute community and stakeholder perspectives and interests in GSP planning and GSP and SGMA implementation in the Temescal Subbasin.

The Technical Advisory Committee will provide review and guidance to the GSA on groundwater-related issues during the development of the GSP that may include:
• Sustainability goals and objectives
• Monitoring programs
• Annual work plans and reports
• Modeling scenarios
• Inter-basin coordination activities
• Projects and management actions to achieve sustainability • Community outreach, including engagement with disadvantaged communities • Local regulations to implement SGMA
• General advice

3. ROLES AND RESPONSIBILITIES
To accomplish the above charge, Technical Advisory Committee members agree to the following:
• Contribute input towards long-term sustainable management of the Temescal Subbasin based on their knowledge and expertise in policy, technical, and community matters • Communicate to other stakeholders and community members about the GSA, GSP process, and SGMA
• Work collaboratively with others on the Technical Advisory Committee • Commit time needed to review material and participate in ongoing discussions • Collectively reflect diversity of interests
• Represent constituents’ perspectives, but also consider broader community input and input from other members during Technical Advisory Committee meeting discussions

3 • Participate in all Technical Advisory Committee meetings for the entire planning process • Partner with the GSA and project team in publicizing public involvement activities

4. PARTICIPATION AND COLLABORATION PRINCIPLES
All Technical Advisory Committee members will work together to create a collaborative, problem-solving environment. The preferred deliberation process is a collaborative process whereby Technical Advisory Committee members choose to cooperate to achieve shared and/or overlapping objectives, in support of the GSA’s direction for the creation of a GSP for the Temescal Subbasin.

By agreeing to serve on the Technical Advisory Committee, members commit to the following principles:
• Commit to a good faith effort.
• Use common conversational courtesy.
• All ideas and point of view have value. All ideas have value in this setting. We are looking for innovative ideas. The goal is to achieve understanding. Simply listen, you do not have to agree. If you hear something you do not agree with or you think is “silly” or “wrong,” please remember that the purpose of the forum is to share ideas. • Be honest, fair and as candid as possible. Help others understand you and work to understand others.
• Share relevant information.
• Avoid editorials. It will be tempting to analyze the motives of others or offer editorial comments. Please talk about your own ideas and thoughts. Avoid commenting on why you believe another participant thinks something.
• Honor time and be concise. People’s time is precious; treat it with respect. • Think innovatively and welcome new ideas. Creative thinking and problem solving are essential to success. Attempt to think about the problem in a new way. • Seek solutions for all – help to integrate each other’s interests into creative solutions that address diverse needs.
• Invite humor and good will.

Meetings will be conducted using a facilitator, who will:
• Maintain a neutral position during Technical Advisory Committee discussions. • Work to ensure that all Technical Advisory Committee members have the opportunity to participate equally.
• Guide meeting discussions per the agenda and manage time. • Provide dialogue activities as needed for productive outcomes. • Enforce the Technical Advisory Committee collaboration principles stated above. • Ask “why” to clarify interests.

4 • Track actions, next steps, and deadlines.
• Participate in agenda preparation as part of meeting the above responsibilities and integrating the Technical Advisory Committee in the planning process.

5. MEMBERSHIP
The intent of the Technical Advisory Committee is to provide broad participation and advice to the GSA. To facilitate effective meetings and manage group size, the Technical Advisory Committee will not exceed 18 members.

The GSA Staff (made up of City of Corona Department of Water and Power staff) will manage its membership and composition and the Staff may make appointments from time-to-time after receiving Technical Advisory Committee recommendations from interested parties to serve on Technical Advisory Committee. When an organization’s representative is no longer able to serve, the organization will recommend a new representative to the Technical Advisory Committee. If the organization withdraws from the Technical Advisory Committee, the Technical Advisory Committee and Staff will identify another organization and corresponding representative to fill that seat and recommend the organization to the GSA for appointment.

The Technical Advisory Committee strives to include a range of interests in groundwater in the Temescal Subbasin as outlined in SGMA. Technical Advisory Committee members live in the Temescal Subbasin or represent organizations with a presence or agencies with jurisdiction in the Subbasin, including:
• All Groundwater Users
• Municipal Well Operators, Public Utilities Commission-Regulated Water Companies, and Private and Public Water Systems
• County and City Governments
• Planning Departments/Land Use
• Local Landowners
• Disadvantaged Communities
• Business and Agriculture
• Rural Residential Well Owners
• Environmental Users
• Water Supply and Management Surface Water Users (if connection between surface and ground water)
No Technical Advisory Committee member shall be compensated by the GSA for preparation for or attendance at meetings of the GSA or any committee created by the GSA. The fiscal responsibility of the Technical Advisory Committee falls under the oversight of the GSA.