APPENDIX H CRYSTAL GEYSER MT. SHASTA FACILITY WASTEWATER DISCHARGE ALTERNATIVES Draft Technical Memorandum Crystal Geyser Mt. Shasta Facility Wastewater Discharge Alternatives

PREPARED FOR: Richard Weklych/CGWC Barbara Brenner/Churchwell White

PREPARED BY: Peter Rude/CH2M Michael Randall/CH2M

DATE: June 17, 2016 (Revised September 16, and October 7, 2016)

PROJECT NUMBER: 677791.03.31.02

This technical memorandum provides descriptions of the four wastewater discharge alternatives for the Crystal Geyser Bottling Facility in Mt. Shasta to be evaluated in the Environmental Impact Report (EIR). The Crystal Geyser Water Company (CGWC) Mt. Shasta Plant is equipped with the following wastewater discharges:  Domestic sanitary sewer pipe line currently connected to the City of Mt. Shasta’s sanitary sewer system.  Industrial process wastewater pipe line historically connected to City sanitary sewer system.  Industrial process rinse wastewater pipe line historically connected to CGWC leach field. The descriptions below define the proposed alternatives for discharge of the three wastewater flow streams defined above. Background The domestic sanitary sewer flows from CGWC are expected to be about the same as from the previous operations at the facility. CGWC will start operations with approximately 30 employees; this will eventually increase to approximately 60 employees. This will result in an average daily flow to the sanitary sewer system of about 300 to 600 gallons per day. Industrial wastewater discharges will range from approximately 20,000 gallons per production day (gppd) to approximately 54,000 gppd for one product line. In 5 to 7 years, when a second bottling line is added, discharges will approximately double, ranging from 40,000 to 100,000 gppd. It is unknown how much industrial wastewater the previous operations at the facility sent to the City sanitary sewer system. Industrial process rinse wastewater discharged to the leach field will range from 5,000 gppd to infrequent peaks of up to 25,000 gppd. When the second bottling line is added, discharges will approximately double, ranging from 10,000 gppd to infrequent peaks of up to 50,000 gppd. The existing leach field is permitted to accommodate 72,000 gallons per day (gpd), however it is designed to be expanded to 108,000 gpd. Previous operations at the facility consisted of two bottling lines and used the leach field to its permitted capacity. The industrial process wastewater peak discharge and industrial process rinse wastewater peak discharge will not be additive; they will not occur at the same time. Wastewater Discharge Alternatives CGWC has identified four alternatives for managing the discharge of the three wastewater flows from the facility. These alternatives are: Alternative 1 – Discharge to City Sanitary Sewer Alternative 2 – Discharge to City Sanitary Sewer and Leach Field Alternative 3 – Discharge to Leach Field during the production of sparkling water Alternative 4 – Onsite Treatment with Discharge to Leach Field and Offsite Irrigation

Alternative 1 Alternative 1 consists of discharging all of the domestic and industrial wastewater to the City of Mt. Shasta’s sanitary sewer system as shown on Figure ALT1-1. This alternative would include direct discharge of domestic wastewater to the City’s sanitary sewer system through the existing connection at the Southwest corner of the facility site. The industrial process rinse water would be discharged to the City Sanitary Sewer. Industrial process water would flow to a series of two below grade concrete holding tanks and then sent to the pH Neutralization System to treat the pH of the flow stream to acceptable pH limits before discharge to the City’s Sanitary Sewer System. Alternative 2 Alternative 2 would involve a combination of discharging domestic wastewater and the industrial wastewater into the City’s sewer, with industrial process rinse water to be discharged into the Plant’s onsite leach field, as currently permitted by the Central Valley Regional Water Quality Control Board (Regional Board), as shown on Figure ALT2-1. This alternative would include direct discharge of domestic wastewater to the City’s sanitary sewer system through the existing connection at the Southwest corner of the facility site. The industrial process rinse water would be discharged to the existing onsite leach field located south of the CGWC Bottling Facility. Industrial process water would flow to a series of two below grade concrete holding tanks and then sent to the pH Neutralization System to treat the pH of the flow stream to acceptable pH limits before discharge to the City’s Sanitary Sewer System. Alternative 3 Alternative 3 would involve discharging domestic wastewater into the City’s sewer, industrial process rinse water to be discharged into the Plant’s onsite leach field, as currently permitted by the Central Valley Regional Water Quality Control Board (Regional Board), and industrial process wastewater from the production of only sparkling water would be discharged to the Leach Field under a new permit with RWQCB, as shown on Figure ALT3-1. This alternative would include direct discharge of domestic wastewater to the City’s sanitary sewer system through the existing connection at the Southwest corner of the facility site. The industrial process rinse water would continue to be discharged to the existing onsite leach field located south of the CGWC Bottling Facility. Industrial process water from the production of sparkling water, would flow to a series of two below grade concrete holding tanks and then sent to the pH Neutralization System to treat the pH of the flow stream to acceptable pH limits before being discharged to the Leach Field System. If two bottling lines operated at full production, the existing leach field would need to be expanded to accommodate the additional flows. Industrial process waste water from the production of sparkling water is relatively clean. A groundwater mixing model was developed to analyze the potential effect on groundwater quality near the leach field when industrial process waste water is discharged through the leach field. The results of the model, show a slight rise in several background constituents, but the constituents are still well within drinking water standards. A copy of the groundwater mixing model technical memorandum prepared by Geosyntec (September 19, 2016) is provide as a separate attachment. This alternative would have to go through the RWQCB report of waste discharge approval process before it could be implemented.

Alternative 4 Alternative 4 would involve discharging the domestic wastewater to the City’s sewer and treating the industrial wastewater onsite, and discharging it to either the onsite leach field or offsite irrigation locations as shown on Figure ALT4-1. This alternative is similar to Alternative 3 with the additional option of land applying the treated wastewater during the irrigation season from May through October. With two bottling lines, the volume of treated wastewater is enough for about 20 acres of irrigated grass fields, to be on CGWC property as shown on Figure ALT4-2. Domestic wastewater would be directly discharged to the City’s sanitary sewer system through the existing connection at the Southwest corner of the facility site. The industrial process rinse water would be discharged to the existing onsite leach field located south of the CGWC Bottling Facility or to the offsite irrigation locations discussed above. Industrial process water would flow to a series of two below grade concrete holding tanks and then sent to a batched pH Neutralization System to treat the pH of the flow stream to acceptable pH limits and then to an onsite treatment system before discharge to the leach field or offsite irrigation field.

Summary Table 1-1 summarizes the four alternatives evaluated for inclusion in the EIR.

Table 1-1: Summary of Wastewater Discharge Alternatives Crystal Geyser Mt. Shasta Facility Wastewater Discharge Alternatives Wastewater Discharge Source

Alternative Domestic Sanitary Industrial Process Industrial Process Sewer Rinse

Wastewater Treatment Alt 1 City Sanitary Sewer City Sanitary Sewer City Sanitary Sewer

Wastewater Treatment Alt 2 City Sanitary Sewer City Sanitary Sewer CGWC Leach Field

Wastewater Treatment Alt 3 City Sanitary Sewer CGWC Leach Field CGWC Leach Field

Wastewater Treatment Alt 4 City Sanitary Sewer Onsite Treatment to CGWC Leach Field Offsite Land Application Irrigation (and Leach Field in Non-Irrigation Season)

8" SS 8" SS 8" SS

4" SS 4" SS

CGWC Bottling Facility

6" SS

8" to pH Neutralization System 8" to pH Neutralization System pH Neutralization System Concrete Tanks

From CGWC Flow Meter Domestic Sewer System 8"

6" 8" 8" SS

8" SS Sewer Manhole To City Sanitary Sewer System

Aerial photo source: Google ©2015, modified by CH2M HILL. Figure ALT1-1 Site Plan: Discharge to City Sanitary Sewer LEGEND Industrial process wastewater to City sanitary sewer Crystal Geyser Water Company 0 100 200 Clean out SS Sanitary sewer Industriality sanitary process sewer rinse wastewater to City sanitary sewer Mt. Shasta, CA Manhole Flow direction DomesticDomestic Sanitary Sanitaryter toSewer Sewer ity sanitary se North Approximate scale in feet

WBG031814043631RDD FigureALT1-1_SitePlan_CitySwrConnection_V1.ai cmont 06/03/16 8" SS 8" SS 8" SS

4" SS 4" SS

CGWC Bottling Facility

6" SS

8" to Leach Field 8" to Sampling pH Neutralization Point System pH Neutralization System Concrete Tanks 8" From CGWC Flow Meters Domestic Sewer System 8" 6"

6" 6" 8" 8" SS

Leach Field 8" SS Sewer Junction Box Manhole To City Sanitary Sewer System

Aerial photo source: Google ©2015, modified by CH2M HILL. Figure ALT2-1 Site Plan: Discharge to City Sanitary Sewer LEGEND Connection and Leach Field Clean out SS Sanitary sewer Industrial process wastewater to City sanitary sewer Crystal Geyser Water Company 0 100 200 Manhole Flow direction Industrial process wastewater to leach field Mt. Shasta, CA Domestic Sanitary Sewer North Approximate scale in feet

WBG031814043631RDD FigureALT2-1_SitePlan_CitySwrConnection_V1.ai cmont 06/03/16 8" SS 8" SS 8" SS

4" SS 4" SS

CGWC Bottling Facility

6" SS

8" to Leach Field 8" to Sampling pH Neutralization Point System pH Neutralization System Concrete Tanks 8" From CGWC Flow Meters Domestic Sewer System 6"

6"

8" SS

Leach Field 8" SS Sewer Junction Box Manhole To City Sanitary Sewer System

Aerial photo source: Google ©2015, modified by CH2M HILL. Figure ALT3-1 Site Plan: Discharge to Leach Field LEGEND during the Production of Sparkling Water Clean out SS Sanitary sewer Industrial process wastewater to leach field Crystal Geyser Water Company 0 100 200 Manhole Flow direction Domestic Sanitary Sewer Mt. Shasta, CA North Approximate scale in feet

WBG031814043631RDD FigureALT3-1_SitePlan_CitySwrConnection_V2.ai cmont 10/07/16 8" SS 8" SS 8" SS

4" SS 4" SS

CGWC Bottling Facility

6" SS

8" to Leach Onsite Treatment Field 8" to System Sampling pH Neutralization Point System 8" 8" pH Neutralization System

8" Concrete Tanks 8" Discharge to From CGWC Onsite Irrigation Discharge to Flow Meter Domestic Sewer Leach Field System 6"

6"

8" SS

Leach Field 8" SS Sewer Junction Box Manhole To City Sanitary Sewer System

Aerial photo source: Google ©2015, modified by CH2M HILL. Figure ALT4-1 Site Plan: Onsite Treatment with Discharge to Leach Field and Onsite Irrigation LEGEND Crystal Geyser Water Company 0 100 200 Clean out SS Sanitary sewer Industrial process wastewater to leach field and onsite irrigation Mt. Shasta, CA Manhole Flow direction Domestic Sanitary Sewer North Approximate scale in feet

WBG031814043631RDD FigureALT4 -1_SitePlan_CitySwrConnection_V3.ai cmont 08/03/16 Crystal Geyser Property (12.0 Acres)

Crystal Geyser Property (11.8 Acres)

CGWC Bottling Facility

Aerial photo source: Google ©2015, modified by CH2M HILL.

0 500 1000 Figure ALT4-2 North Approximate scale in feet Offsite Land Application Sites Crystal Geyser Water Company Mt. Shasta, CA

WBG031814043631RDD FigureOP4-2_OffsiteLandApplicationSites_V3.ai cmont 06/16/16

Rev ised Technical Memorandum

Date: September 19, 2016 (Revised November 14, 2016) To: Richard Weklych (CGWC) and Pete Rude (CH2M HILL) From: Jeffrey Zukin, Senior Geologist, Geosyntec Consultants Subject: Summers Model – CGWC Shasta Facility

Introduction

Geosyntec Consultants (Geosyntec) has prepared this Revised Technical Memorandum to present results of effluent-groundwater mixing simulations for the Crystal Geyser Water Company (CGWC) Shasta bottling plant located at 210 Ski Village Drive in Mt. Shasta, California (Figure 1). Geosyntec’s understanding is that simulation (i.e., modeling) results will be used to support the current environmental impact analysis that is being conducted for the bottling plant. CGWC would like to have an option of discharging their industrial process wastewater to the bottling plants’ leach field when producing both flavored and unflavored sparkling water. This waste discharge option is referred to as Waste Water Treatment Option 3 in the current impact analysis of the Draft EIR. To support evaluation of Waste Water Treatment Option 3, CGWC asked Geosyntec to evaluate the potential concentrations of select compounds in groundwater due to future industrial process wastewater discharge in the leach field area. This Revised Technical Memorandum includes a response to a CVRWQCB request dated November 2, 2016 that the effluent-groundwater mixing simulations evaluate “worst- case conditions” by considering anticipated lower and upper values of aquifer hydraulic conductivity.

Hydrogeology and Modeling Methodology

The plants’ leach field is located south of the bottling plant (Figure 2) and was used in the past by former owners of the bottling facility to discharge industrial process waste water. Discharge to the leach field is currently allowed under an existing Waste Discharge Order No. 5-01-233 issued by the Central Valley Regional Water Quality Control Board (CVRWQCB).1 Plans prepared by CH2M HILL show that the leach

1 CH2M Hill, September 30, 2015, Crystal Geyser Request to Commence Operations Under Existing Waste Discharge Requirement Order No 5-01-233.

Summers Model Memorandum September 19, 2016 (Revised November 14, 2016) Page 2 field currently consists of nine rows of shallow buried perforated pipes that cover an area approximately 160 feet by 200 feet.2 Boring logs and regional geological maps indicate that the leach field discharges waste water into glacial outwash or glacial alluvial deposits that generally consist of clays, sands, gravels and boulders. Underling the glacial alluvial material is volcanic rocks.

Industrial waste water discharged in the leach field will percolate downward through the glacial alluvial material and then encounter a shallow groundwater table that occurs at approximately 40 feet below ground surface (ft bgs). Based on the Well Completion Reports for the Site Domestic well (DOM-1) located west of the bottling plant building, and monitoring well logs for MW-1, MW-2 and MW-3 (Figure 2), the glacial alluvial material underlying the leach field area is estimated to be present to a depth of approximately 140 ft bgs. It is also estimated, based on lithologic descriptions of sand, gravel and boulders, and groundwater measurements, that the shallow aquifer in the glacial alluvium deposit is roughly 100 feet thick. Shallow groundwater in the glacial alluvial material generally flows westward.3

To evaluate the mixing of discharged industrial waste water with shallow groundwater beneath the leach field area and the resulting groundwater concentrations, Geosyntec utilized the Summers model.4 The Summers model employs a simple mass balance and simulates dilution of discharge effluent in groundwater. The Summers model assumes no attenuation of the effluent in the aquifer and complete mixing of industrial waste water and groundwater.

2 CH2M HILL, July, 2001, Dannon Leach Field Design Drawings. 3 Geosyntec Consultants Fourth Quarter 2015 Monitoring Report dated January 27, 2015; First Quarter 2016 Monitoring Report dated April 30, 2016; and, Second Quarter 2016 Monitoring Report dated July 29, 2016. 4 Summers, K. S., Gherini, and C. Chen, 1980, Methodology to Evaluate the Potential for Groundwater Contamination for Geothermal Fluid Releases, EPA-600/7-80-117, U.S. EPA/IERI, Cincinnati, Ohio.

Summers Model Memorandum September 19, 2016 (Revised November 14, 2016) Page 3

The Summers model calculation is as follows:

Cf = QsCs + QaCa (Equation 1) Qs + Qa where:

Cf = resulting concentration in groundwater in milligrams per liter (mg/l). Qs = volumetric flow rate of waste water migrating downward through the unsaturated zone in feet3/year (ft3/yr). Cs = concentration of compound or solute in waste water (mg/l). Qa = volumetric flow rate of groundwater laterally moving through the aquifer underlying the unsaturated zone (ft3/yr). Ca = initial concentration of a compound or solute in groundwater (mg/l).

Qa in Equation 1 is calculated from Darcy’s Law and a property-specific mixing zone calculation (see Equation 3). Darcy’s Law is as follows:

Qa = KiAa (Equation 2) where:

K= hydraulic conductivity of groundwater aquifer (ft/yr). i = hydraulic gradient of the groundwater in the aquifer (dimensionless). 2 Aa = cross-section area of aquifer where mixing of waste water occurs (ft ).

Aa is generally considered to be equal to the length of the source area perpendicular to groundwater flow (W) multiplied by a calculated mixing zone in the aquifer (m). The

Summers Model Memorandum September 19, 2016 (Revised November 14, 2016) Page 4 thickness of the mixing zone, m, is calculated with the following equation5:

m = (0.0112L2)0.5 + d[1- exp(-LI/Kid] (Equation 3) where:

d = aquifer thickness (ft). L = source length parallel to groundwater flow direction (ft). I = infiltration rate (ft/yr). K= hydraulic conductivity of groundwater aquifer (ft/yr). i = hydraulic gradient of the groundwater in the aquifer (dimensionless). exp = the inverse of natural log.

Qs, in Equation 1, is typically calculated from the area affected and infiltration rate:

Qs = LWI (Equation 4) where:

L = source length parallel to groundwater flow direction (ft). W = source length perpendicular to groundwater flow (ft). I = infiltration rate (ft/yr)

In the current analysis, Qs was estimated based on the expected annual industrial waste water flow to the leach field.

Model Input

The following parameters were used to calculate Qa and Qs for the proposed discharge at the CGWC Shasta operation. The parameters are also summarized in Table 1.

5 USEPA (1996). Soil Screening Guidance: Technical Background Document, May 1996. U.S. Environmental Protection Agency, Office of Emergency Response: Washington, DC, EPA/540/R-95/128 PB96-963502.

Summers Model Memorandum September 19, 2016 (Revised November 14, 2016) Page 5

 Boring logs for the monitoring wells MW-1, MW-2, and MW-3 indicate that the shallow glacial alluvial aquifer below the leach field area generally consists of sand, gravel, and boulders. Hydraulic conductivity, K, was assumed to equal 265 ft/day (96,725 ft/year) which is the average value between representative K values for medium sand (40 ft/day) and coarse gravel (490 ft/day) as reported by Todd.6  Hydraulic gradient, i, was estimated to be 0.038 which is the average of the hydraulic gradient calculated using groundwater levels measurements collect on September 14, 2015 and March 15, 2016 (3rd Quarter 2015 and 1st Quarter 2016 monitoring events).3  Source length parallel to groundwater flow, L, is equal to approximately 160 feet. This is the east-west dimension of the leach field. Shallow groundwater is thought to flow generally westward in the shallow aquifer below the leach field.  Source length perpendicular to groundwater flow, W, is 200 feet. This is the north-south the dimension of the leach field.  Infiltration rate, I, was estimated to be 1,363,550 ft3/yr or 42.6 ft/yr given the dimensions of the leach field (L and W). This figure was derived based on information presented in the CH2M HILL 2015 report1 and personal communication with CGCW staff (Richard Weklych, 2016) who reported that that the planned industrial waste water discharge to the leach field is expected to occur at an approximate rate of 5,000 gallons per day (gpd) for 250 days a year, and 25,000 gpd for 50 days a year. In addition, industrial waste water discharge initially planned to be discharged to the city sewer may be discharged to the leach field at a rate of 20,000 gpd, 250 days a year and 54,000 gpd, 50 days a year. Assuming these rates it is estimated that 10,200,000 gallons per year (gal/yr) or 1,363,550 ft3/yr may be discharged in the leach field area. This flow and volume represents peak production at 6 days per week with one production line operating. It should be noted that domestic sewage will continue to flow to the City sanitary sewer through a separate piping system.  Shallow glacial alluvium aquifer thickness, d, in the leach field area was estimated to be approximately 100 feet, based on the DOM-1 well log, and the MW-1, MW-2, and MW-3 monitoring well logs.  The mixing zone, m, is calculated to equal 18.77 feet using Equation 3.

6 Todd, K. T., 1980, Groundwater Hydrology, 2nd edition.

Summers Model Memorandum September 19, 2016 (Revised November 14, 2016) Page 6

Certain dissolved constituents and general minerals were selected for modeling based on materials and chemicals that CGWC will add to source waters and discharge to the leach field. CGWC reports that constituents that will be discharged include the chemicals that will be used for sanitation of their equipment: hydrogen peroxide, peroxyacetic acid, acetic acid, nitric acid, bleach or chlorine (NaClO), hydrochloric acid, vinegar, caustic soda (NaOH and NaCl), sodium xylene sulfonate, and cocamine oxide. Other constituents that will be added include fruit flavoring extracts. Based on the chemical makeup of these chemicals, the following constituents and general minerals were selected for modeling: Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD), sodium (Na), chloride (Cl), sulfate (SO4), and boron (B). Because all chemicals used in CGWC processes are food grade products, no priority pollutants such as listed volatile organic compounds, semi-volatile organic compounds, or Title 22 metals are believed to be contained in the products used by CGWC. In addition, the food grade acids used in the process are expected to rapidly degrade into benign substances.

Model inputs for calculating dissolved constituents and general minerals in groundwater include Ca and Cs (see Equation 1). These model inputs are summarized in Table 2. Ca, the initial concentrations of constituents in the shallow groundwater, was estimated based on March 16, 2016 and June 22, 2016 sampling results for monitoring wells MW-1 and MW-2. Wells MW-1 and MW-2 are located directly adjacent to the leach field. Ca for TDS, COD, Na, Cl, SO4, and B is shown in Table 2.

To estimate Cs CGWC referred Geosyntec to general mineral data collected in effluent at their current operations in the City of Calistoga.7 The CGWC Calistoga facility currently produces flavored mineral water and the operations at the facility are thought to be a conservative analog for proposed operations at the Mt. Shasta Facility.1 Based on data presented in the CH2M HILL (2015) report1 and 2013 testing conducted by CGWC, the TDS of the CGWC Calistoga industrial source water (City water) is 165 mg/l and the TDS in their product source water is 540 mg/L. Furthermore, CGWC estimates that the Calistoga facility effluent is composed of 75% Calistoga City water and 25% product source water. Using these values, it is estimated that a blend of these source waters would have a TDS of approximately 259 mg/L. The CH2M HILL 2015 report shows that Calistoga effluent has a TDS of 360 mg/l. By comparing the blended source water TDS and effluent TDS at the Calistoga facility, we estimate that 101 mg/l

7 A similar strategy was followed in CH2M HILL’s September 30, 2015 report.

Summers Model Memorandum September 19, 2016 (Revised November 14, 2016) Page 7 of dissolved constituents is being added to the City water/product blend (i.e., 360 mg/L - 259 mg/L = 101 mg/L) from chemicals that CGWC is using at their Calistoga facility.

Performing a similar analysis for other specific constituents in the Calistoga effluent, such as COD, sulfate and B, results in an estimated addition of approximately 199.5 mg/L, 17.8 mg/L, and 0.392 mg/L, respectively, for these constituents.8 Na and Cl would also be generated from the cleaning processes (use of bleaches, sodium hydroxide, etc.) and discharged in the leach field. However, applying the same methodology as above does not result in a realistic estimate because, based on the CH2M HILL 2015 report, sodium and chloride concentrations are lower in the Calistoga effluent than in the source water. In lieu of this estimating technique, we conservatively assume that, on average, 50 mg/L of Na and 50 mg/l Cl is added to the effluent (i.e., assumes almost all of the 101 mg/L TDS added consists of Na and Cl).

Extrapolating the above derived values from the Calistoga facility, the values are then “added” to the concentrations in the source water at the Shasta facility (DEX-6) to estimate the chemistry of the effluent that will be discharged in the leach field (Table 2). That is, the effluent would have a TDS of approximately 211 mg/l (101 mg/L + 110 mg/), a COD of 199.5 mg/L (199.5 mg/L + ND), a sodium concentration of 61 mg/l (50 mg/l +11 mg/l), a chloride concentration of 51.5 mg/l (50 mg/l +1.5 mg/l), a sulfate concentration of 18.4 mg/l (17.8 mg/l + 0.6 mg/l) and a boron concentration of 0.417 mg/l (0.392 mg/l + 0.025 mg/l). Table 2 provides a summary of preliminary estimated waste water concentrations (Cs) for the Shasta plant using the above described methodology.

Model Results

Model parameters summarized above and in Tables 1 and 2 were input into Equations 1-4 to derive resulting concentrations in shallow groundwater beneath the leach field (Cf). The model results are summarized in Table 2. Based on these model results, impacts to shallow groundwater quality from CGWC operations are predicted to be relatively low. For example, the model predicts that only a 9 mg/L increase in TDS and a 4-5 mg/L increase in both Na and Cl would occur in the shallow groundwater beneath the leach field area.

8 City of Calistoga 2014 water quality report used to estimate sulfate and boron concentrations in industrial City source water.

Summers Model Memorandum September 19, 2016 (Revised November 14, 2016) Page 8

Response to CVRWQCB Request Dated November 2, 2016

In a letter dated November 2, 2016 the CVRWQB indicated that they found that the groundwater mixing analysis presented above is based on conservative parameters with the exception of the estimated K value (265 ft/day).9 The CVRWQCB requested that the model consider “worst-case conditions” by considering that anticipated range of K values. As presented in the Model Input section of this memorandum, anticipate K values range between 40 ft day to 490 ft day. These lower and upper K values were inputted into the mixing model to derive a range of Cf that takes into account potential K variability. Results of this variability analysis are summarized in Table 3. The mixing model predicts that under a worst-case scenario (i.e., lower K value of 40 ft/day and conservative parameters) TDS would increase by approximately 30 mg/L, and Na and Cl would increase by 15 to 16 mg/L. Even using this “worst-case condition”, the calculated estimates of Cf for the anticipated K range is still well below available California MCLs (Table 3).

*****

9 The estimate K was based on an average K value for lithologic materials occurring in the shallow glacial alluvial aquifer. Table 1

Summers Model Parameters

Model Description unit Value Parameters L Length of infiltration area ft 160 parallel to groundwater flow W Length of infiltration area ft 200 perpendicular to groundwater flow I Infiltration rate (effluent ft/yr 42.61 discharge) K Hydraulic conductivity of ft/day 40-490 Shallow Aquifer Average = 265 i Hydraulic gradient ft/ft 0.038 d Shallow aquifer thickness ft 100 m Mixing zone thickness ft 18.77

1: Assumes representative hydraulic conductivity of coarse sand and coarse gravel as reported by Todd (1980), Representative K for medium sand reported as 39 ft/day and representative K for coarse gravel reported as 492 ft/day. Average K is estimated to equal to approximately 265 ft/day

Table 2

Groundwater and Effluent Concentrations (Ca and Cs), and Model Results (Cf)

Constituent Unit Shallow Source Water Estimated Resulting CA Groundwater Concentration Effluent Concentration MCL Concentration (DEX-6)2 Concentration in Shallow 1 (Ca) (Cs) Groundwater (Cf) TDS mg/l 110 110 211 119 1,000 COD mg/l 3.5 (ND) 0 199.5 21 -- Na mg/l 7.6 11 61 12.4 -- Cl mg/l 0.8 1.5 51.5 5.4 250 SO4 mg/l 1.2 0.61 18.4 2.7 250 B mg/l 0.0059 0.025 (ND) 0.417 0.0429 -- 1: Based on average of constituent concentrations detected in samples collected from MW-1 and MW-2 on March 16, 2016 and June 22, 2016. COD in the monitoring wells was reported to be <7 mg/L, consequently, half of the reporting limit (3.5 mg/l) was chosen for the modeling input for COD. 2: Constituent concentration detected in sample collected from DEX-6 in 2012. B concentration in DEX-6 was reported to be <0.050 mg/L, consequently, half of the reporting limit (0.025 mg/L) was chosen for modeling input for B. COD concentration was not analyzed and was assumed to be zero. CA MCL: California Maximum Contaminant Level for drinking water. MCLs for TDS, Cl, and SO4 are secondary standards. mg/l: milligrams per liter ND: Not detected

Table 3

1,2 Model Results (Cf) For Variable K Inputs

Constituent Unit Cf Cf Cf CA K = 40 ft/day K = 265 ft/day K = 490 ft/day MCL

TDS mg/l 140 119 115 1,000 COD mg/l 62.6 21 13.9 -- Na mg/l 23.7 12.4 10.4 -- Cl mg/l 16.1 5.4 3.5 250 SO4 mg/l 6.4 2.7 2.1 250 B mg/l 0.1298 0.0429 0.0277 --

1: Inputs other the K and the calculated mixing zone thickness (m) remain the same as presented in Tables 1 and 2. 2: Note that the calculated mixing zone thickness (m) for K = 40 ft/day is 28.49 ft, m for K = 265 ft/day is 18.77ft, and m for K = 490 ft/day is 17.93 ft. Cf: Resulting Concentration in Shallow Groundwater CA MCL: California Maximum Contaminant Level for drinking water. MCLs for TDS, Cl, and SO4 are secondary standards. mg/l : milligrams per liter 3,0001,500 0 3,000 Feet

Site Location Map

210 Ski Village Drive Mount Shasta, California

Figure Legend Approximate Site Location 1 Santa Barbara October 2012 SantaBarbara-01\Data P:\GIS\SB0639CGShasta\Projects\Fig01_Site_Location_Map.mxd - HLE 20121015 DEX-06

DEX-03A

DEX-01 Big Spring

Irrigation Ditch Well DOM-1

Leach Field Area

MW-03 Stream Well MW-01 (Lower) P-03 P-04 P-01 600 300 0 600 Feet P-02 MW-02

Site Plan and Monitoring Locations Legend 210 Ski Village Drive Color Code: Surface Water Station Spring Mount Shasta, California Other Monitoring Location Piezometer Site Boundary WDR Monitoring Location Monitoring Well Big Springs Creek Figure Notes Irrigation Ditch Site boundary and monitoring well locations are approximate. 2 Locations for MW-01, MW-02, and MW-03 shown per Golder 2013 report and well completion reports. Santa Barbara July 2014 SantaBarbara-01\Data P:\GIS\SB0639 - CG Shasta\Projects\Phase 08\Fig02_Site_Plan_and_Monitoring_Locations.mxd STM 20140711 STM 08\Fig02_Site_Plan_and_Monitoring_Locations.mxd Shasta\Projects\Phase CG - P:\GIS\SB0639 SantaBarbara-01\Data