Beale_WDR_permit.pdf

KARL E. LONGLEY SCD, P.E., CHAIR PATRICK PULUPA, ESQ., EXECUTIVE OFFICER

11020 Sun Center Drive #200, Rancho Cordova, CA 95670 www.waterboards.ca.gov/centralvalley

25 January 2019

Mr. Calvin Hendrix Dep. Base Civil Engineer Beale AFB WWTF

6425 B-Street Beale AFB, CA 95903

NOTICE

TENTATIVE WASTE DISCHARGE REQUIREMENTS

FOR

UNITES STATE AIR FORCE

BEALE AIR FORCE BASE WASTEWATER TREATMENT FACILITY

YUBA COUNTY

TO ALL CONCERNED PERSONS AND AGENCIES:

Enclosed are tentative Waste Discharge Requirements (WDRs) for the Beale Air Force Base Wastewater Treatment Facility in Yuba County. A public hearing concerning this matter will be held during the Central Valley Regional Water Quality Control Board (Central Valley Water Board) meeting scheduled for:

DATE: 4/5 April 2019 TIME: 9:00 a.m.

PLACE: Regional Water Quality Control Board, Central Valley Region

1685 “E” Street Fresno, CA 93706-2007

Any comments or recommendations you may have concerning the enclosed tentative Order must be submitted to this office by 5:00 pm on 26 February 2019 in order for us to give them full consideration prior to the 4/5 April 2019 meeting. Comments received after this time will not be considered or included in the administrative record unless allowed by the Board’s Chair.

In order to conserve paper and reduce mailing costs, a paper copy of the tentative Order has been sent only to the Dischargers. Interested parties are advised that the full text of the Order is available on the Central Valley Water Board’s web site at http://www.waterboards.ca.gov/centralvalley/board_decisions/tentative_orders/index.shtml under the heading of “Discharger-Specific Orders for Future Regional Board Meetings”.

http://www.waterboards.ca.gov/centralvalley http://www.waterboards.ca.gov/centralvalley/board_decisions/tentative_orders/index.shtml

T E N T A T I V

CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD

CENTRAL VALLEY REGION

ORDER R5-20XX-XXXX

WASTE DISCHARGE REQUIREMENTS

FOR

UNITED STATES AIR FORCE

BEALE AIR FORCE BASE WASTEWATER TREATMENT PLANT

The California Regional Water Quality Control Board, Central Valley Region, (hereafter Central Valley Water Board) finds that:

1. On 15 August 2018, the United States Air Force submitted a Report of Waste Discharge

(RWD) to apply for revised Waste Discharge Requirements (WDRs) for an existing wastewater treatment plant (WWTP), which serves Beale Air Force Base in Yuba County.

Additional information to complete the RWD was submitted on 4 September 2018, 6 November 2018, and 6 December 2018.

2. The United States Air Force (the Discharger) owns and operates the Beale Air Force Base (AFB) Wastewater Treatment Plant (WWTP) and is responsible for compliance with these Waste Discharge Requirements (WDRs).

3. The facility (WWTP) is at 6425 B Street at Beale AFB (Section T14N, R5E, MDB&M) (facility identification number 124), as shown on Attachment A, incorporated herein.

4. WDRs Order 5-01-087, adopted by the Central Valley Water Board on 27 April 2001, prescribes requirements for the discharge. Order 5-01-087 limits the average dry weather flow to the total design capacity of the ponds and treatment plant. Due to the age of the existing permit, an updated permit is required. Therefore, Order 5-01-087 will be rescinded and replaced with this Order.

Existing Facility and Discharge

5. The WWTP collects, treats, and disposes domestic and industrial wastewater from approximately 800 buildings located on base (335 single family units, 218 multi-family units, and 250 commercial, industrial, and institutional facilities). The WWTP is located in the southwest portion of the base, as shown on Attachment B, incorporated herein. The annual average influent flow rate for 2017 is 0.41 million gallons per day (mgd). The average dry weather flow, July through September 2017, is 0.29 mgd.

6. The WWTP treatment and disposal system consists of a headworks, a primary clarifier, two trickling filters, a secondary clarifier, a chlorination unit, effluent ponds, and land application areas (LAAs), as shown on Attachment C, incorporated herein. The wastewater is treated to disinfected secondary-23 recycled water requirements. An onsite generator provides backup power sufficient to run the entire WWTP in the event of a power outage.

7. Potable water for the Base is supplied by domestic wells located in the western portion of the Base which are sampled annually for water quality. A summary of the results for samples collected in December 2017 are shown below.

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Domestic Well Water Quality 1

Constituent 2 Results Units

Total Dissolved Solids 3 241 mg/L

Bicarbonate as hydroxide ND mg/L

Alkalinity 156 mg/L

Total Recoverable Boron 54.3 mg/L

Chloride 34.3 mg/L

Total Recoverable Iron 363 µg/L

Total Recoverable Manganese 161.3 µg/L

Nitrate as nitrogen 2.14 mg/L

Total Recoverable Potassium 2.1 mg/L 1 Composite samples from the domestic wells. Table Reference: Figure 2.2.5 of RWD (Beale AFB, 2018) 2 Results of select constituents are shown.

3 As reported in the Second Quarter 2018 Groundwater Monitoring Report.

ND = not detected at or greater than the reporting limit of 1 mg/L

8. The sanitary sewer collection system is comprised of 11 sewer lift stations, approximately 38 miles of gravity lines, 8,000 feet of force main, and seven oil/water separators. A contractor is responsible for inspecting and cleaning the separators on a periodic basis.

9. Inflow and infiltration (I/I) into the sanitary sewer system is an on-going issue and the Discharger continues to investigate, conduct studies, and make repairs to the collection system. Between 2008 and 2017, an average of approximately 38.7 million gallons (MG) per year of I/I is entering the system.

10. Two small groundwater remediation treatment systems, CG041-017 and TU002, are located in the eastern portion of the Base and discharge treated groundwater into the sanitary sewer collection system. The remediation systems are operated by the Air Force Civil Engineer Center (AFCEC), with oversight by the Central Valley Water Board, Department of Toxic Substances Control (DTSC), and other regulatory agencies. In 2017, CG041-17 and TU002 discharged approximately 6.6 MG and 0.39 MG, respectively, of treated groundwater into the sewer system. The effluent from both systems are sampled prior to discharging to the sewer system. Both treatment systems are designed to capture any untreated water passing through the remediation system due to system failures, which prevents untreated groundwater from discharging to the sewer system. A complete list of documents for all Air Force Bases, including documents associated with the CG041-017 and TU002 remediation systems, can be found at http://afcec.publicadmin-record.us.af.mil/.

11. Volatile organic compounds (VOCs) have not been detected greater than Maximum

Contaminant Levels (MCLs) in any effluent samples from the TU002 treatment system since it began operating in 2001.

12. The CG041-17 treatment system began operating in 2001. The most recent exceedance of an

MCL for VOCs from the CG041-17 treatment system was reported in May 2012 for 1,1,2,2-tetrachloroethane. No exceedances in the effluent from the remediation system have been reported since 2012.

http://afcec.publicadmin-record.us.af.mil/

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13. Influent flow rates to the WWTP, including flows from the CG041-17 and TU002 groundwater treatment systems and I/I estimates, averaged 13.48 MG per month between 2014 and 2017.

Influent flow rates are summarized below.

WWTP Influent Flow Rates

Month (MG/mo)

2014 2015 2016 2017 Average

Monthly Flow

January 4.24 8.48 29.93 48.28 22.73

February 14.46 13.36 10.96 43.55 20.58

March 20.48 8.41 33.81 17.78 20.12

April 9.69 7.82 9.64 20.79 11.96

May 6.89 6.91 8.45 9.50 7.94

June 7.26 7.14 8.07 9.57 8.01

July 8.08 8.23 7.03 15.46 9.7

August 7.95 7.88 8.21 17.09 10.82

September 6.66 6.55 11.02 13.61 9.46

October 8.07 7.11 12.04 11.36 9.63

November 10.18 8.36 12.57 13.4 11.13

December 33.59 12.21 22.78 10.13 19.68

Yearly Flow

(MG)

137.55 102.46 174.51 230.52

MG/mo = million gallons per month

14. Wastewater enters the WWTP through a reinforced concrete pipe and discharges to the headworks, which contains an automated bar screen, a flume, and a pH meter. Influent wastewater samples are collected from the headworks. A conveyor removes, washes, and dewaters the collected solids which are then dumped into garbage bags in a compactor. The garbage bags are removed from the compactor and disposed of in dumpsters. Wastewater then enters a wet well for the influent pumps. From the headworks, the wastewater is pumped to a primary clarifier.

15. The primary clarifier reduces the concentration of settleable solids and floating materials in the wastewater stream. Sludge removed from the clarifiers is pumped to anaerobic sludge digesters. Sludge and scum from the primary clarifier are treated in primary and secondary anaerobic digesters. The sludge is treated to “Class B” Pathogen Reduction Standards as defined in 40 CFR 503 regulations, which requires a mean cell residence of 15 days at 35 to 55 degrees Celsius and 60 days at 20 Celsius for anaerobic digestion. Both the primary and secondary digesters have a liquid holding volume of 382,000 gallons. Treated sludge is dried in 32 cement lined drying beds, located in the western portion of the WWTP, where approximately one drying bed is filled per month with sludge. The sludge remains on the beds for a minimum of three months, in accordance with “Class B” Pathogen Reduction Standards.

Sludge is tested for acceptance and then disposed of every three years at the Ostrom Road Landfill, located just south of the Base. The drying beds are equipped with a drain system that returns any wastewater back to the headworks.

16. Effluent from the primary clarifier is pumped to two trickling filters to remove organic matter from the wastewater. The filters are aerobic attached-growth, biological treatment processes.

Each filter is 100 feet in diameter and approximately 6 feet deep. Rocks are used as the bed

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on which the microorganisms attach themselves. After flowing through the rock bed, the wastewater flows out of the filters through an underdrain system and enters the secondary clarifier.

17. The secondary clarifier removes settleable solids (sludge) that have sloughed off from the trickling filters. The solids are removed from the clarifier and returned to the influent sewer main upstream of the headworks. Wastewater exits the secondary clarifier and flows through a chlorine contact basin. A summary of the monthly maximums and averages for biochemical oxygen demand (BOD) and total suspended solids (TSS) in 2017 for wastewater in the headworks, primary clarifier, and secondary clarifier is shown below.

Wastewater Monitoring (mg/L)

Influent 1

Primary Clarifier

Secondary Clarifier

BOD

maximum 298 199 40.1 average 87.1 38.4 9.1

TSS

maximum 940 266 73 average 66.4 21.7 7.8 1 Sample collected from the headworks.

18. The chlorine contact basin is constructed of concrete and has a volume of approximately 55,200 gallons. Sodium hypochlorite is used as the disinfecting agent to kill pathogenic bacteria in the treated effluent. A chlorine analyzer paces the chlorine feed pump and maintains a chlorine concentration in the contact basin between 1.5 and 1.8 parts per million (ppm). Wastewater quality from the chlorine contact basin is summarized below.

Effluent Monitoring Results 1

Constituent 2015 2016 2017 Effluent Limits

30 Day Average 2

TDS (mg/L) 598 550 547 350

Chloride (mg/L) 182 231 201 NE

Mercury (µg/L) 0.2 ND ND 0.2

Nitrate (mg/L) 26 24 27.3 NE

Nitrite (mg/L) 1.4 0.9 1.0 NE

TKN (mg/L) 19.1 13.2 11 NE

TN (mg/L) 29.4 24.4 30 NE

Cadmium (µg/L) 1.8 3 1.1 1.3

Copper (µg/L) 17 29.3 18 20

Sodium (mg/L) 92.8 146 89.4 NE

Boron (µg/L) 191 281 197 250 1 Table C3 in the Second Quarter 2018 Groundwater Monitoring Report.

Concentrations shown are the maximum monthly average for the year.

2 Effluent limits required in the 2001 WDRs.

TN = total nitrogen TKN = Total Kjeldahl Nitrogen NE = not established ND = not detected Concentrations in bold exceed an effluent limit.

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19. The WWTP effluent is sampled for total coliform at the outfall of the chlorine contact basin.

Total coliform results for Title 22 requirements for disinfected secondary-23 recycled water cannot exceed 23 MPN/100mL as a 7-day median and cannot exceed 240 MPN/100mL in more than one sample in any 30-day period. While the total coliform results for the 7-day median have not exceeded 23 MPM/100 mL in the last three years (2015, 2016, and 2017), there are several exceedances of the 240 MPN/100 mL requirement. The number of exceedances for each month for a three-year period is shown below.

Number of Total Coliform Results Exceeding 240 MPN/100mL 1

2015 2016 2017

January -- -- 3

February -- -- 5

March -- 3 2

April -- -- --

May -- -- --

June -- 2 --

July -- 2 --

August -- -- --

September 2 -- --

October -- -- 2

November -- -- --

December -- -- -- -- = value did not exceed 240 MPN/100mL in more than one sample for the month.

1 Between 2015 and 2017, the 7-day median of less than 23

MPN/100mL limit for coliform was not exceeded.

20. Effluent from the chlorine contact basin flows by gravity to the effluent pond. The pond is concrete lined with a capacity of approximately 2.6 million gallons, where the treated effluent is stored and aerated by a floating surface aerator.

21. A significant source of influent flow to the effluent pond, in addition to the effluent from the WWTP, is from groundwater remediation treatment plant CG044-13, which began operating in 1994. The system was installed to remediate groundwater contamination associated with Landfill No. 1 (Site LF013), located just west of the sludge drying beds at the WWTP. The remediation system is operated and regulated by AFCEC, with oversight by the Central Valley Water Board, DTSC, and other regulatory agencies. Extracted groundwater from Site LF013 is treated by an air stripping process to remove trichloroethene (TCE) and other VOCs. The system is controlled through a Supervisory Control and Data Acquisition (SCADA) system.

The treatment system is designed so that it cannot operate without all components of the system being active (i.e., the extraction system cannot operate without the air stripper blowers or conveyance pumps operating). This control prevents releases of untreated groundwater to the effluent pond at the WWTP. The treated water is discharged to the effluent pond where it then commingles with treated effluent from the WWTP. The effluent from the remediation system is analyzed for numerous VOCs prior to discharging to the effluent pond. A complete list of documents for all Air Force Bases, including documents associated with the CG044-013 remediation system, can be found at http://afcec.publicadmin-record.us.af.mil/.

http://afcec.publicadmin-record.us.af.mil/

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22. Since the operation of the groundwater remediation treatment system began in 1994, TCE concentrations in effluent from the groundwater remediation system have exceeded the MCL in two samples; one collected in October 2001 and one in July 2010. No other VOCs have exceeded MCLs.

23. A summary of the volume of effluent produced by the Site CG044-013 groundwater treatment that is discharged to the effluent pond is shown below.

Site CG044-013 Effluent Flow from Remediation System to Effluent Pond

Total Air Stripper Effluent (MG/mo) Average Monthly Flow

(Mgal/mo) 2014 2015 2016 2017

January 12.51 10.00 6.02 1.22 7.44

February 12.23 10.94 9.87 0 11.01

March 8.30 13.2 13.38 4.87 9.19

April 4.90 13.2 13.20 2.82 8.53

May 5.15 13.77 12.75 10.68 10.59

June 5.73 13.36 13.70 13.05 11.46

July 9.36 12.50 13.34 7.44 10.66

August 12.46 12.15 13.52 0 12.71

September 8.66 12.98 12.88 0 11.51

October 7.24 13.32 13.87 3.99 9.61

November 8.47 12.44 12.64 13.22 11.69

December 5.18 8.76 8.49 14.3 9.18

Average Yearly Flow

(MG)

8.35 12.22 11.72 7.98

MG/mo = million gallons per month

24. Total flows to the effluent pond, which includes effluent from the Site CG044-013 remediation system and the WWTP, are summarized below.

Average Monthly Wastewater Flows to the Effluent Pond (MG/mo)

Average

WWTP Effluent

Average Remediation

System Effluent

Average Wastewater Effluent to

Pond

January 22.73 7.44 30.17

February 20.58 11.01 31.59

March 20.12 9.19 29.31

April 11.96 8.53 20.49

May 7.94 10.59 18.53

June 8.01 11.46 19.47

July 9.7 10.66 20.36

August 10.82 12.71 23.53

September 9.46 11.51 20.97

October 9.63 9.61 19.24

November 11.13 11.69 22.82

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Average Monthly Wastewater Flows to the Effluent Pond (MG/mo)

Average

WWTP Effluent

Average Remediation

System Effluent

Average Wastewater Effluent to

Pond

December 19.68 9.18 28.86

25. Treated wastewater from the effluent pond is pumped to Pond 4, located approximate 3,000 feet southeast of the WWTP. Pond 4 is unlined, covers approximately 27 acres, and is up to 19 feet deep for a total holding capacity of 109 million gallons, not including 2 feet of freeboard. Treated effluent is stored in this pond prior to being pumped to the A-Street Pond at the golf course or an irrigation field (Irrigation Field #1).

26. In the event of a process failure at the WWTP that could result in discharges of partially treated wastewater, WWTP staff would first attempt to store the wastewater in the effluent pond. When the capacity of the effluent pond is approached, the partially treated wastewater would then be pumped to Pond 4, which would be used to provide storage for the 20-day period required by Title 22. In addition, effluent from the CG044-13 groundwater treatment remdiation system would cease until the process failure at the WWTP has been corrected.

27. The A-Street Pond is a small unlined holding pond near the golf course. The pond has a surface area of approximately two acres and a depth ranging from three to eight feet with a storage volume of approximately two million gallons. The wastewater from the A-Street pond is used to irrigate the 120-acre on-base, restricted access golf course. Sprinkler irrigation occurs at night with most of irrigation taking place in the summer months.

28. Irrigation Field #1 (West Irrigation Field) is located approximate 3,000 feet northwest of

Pond 4 and is used to dispose treated wastewater when water is not needed for golf course irrigation. Non-edible vegetation on the 40-acre field is sparse and consists of native grasses or fodder and non-native invasive weeds. There are no managed or planted agricultural grasses or seed crops grown on site and the field is not mowed. The field is sprinkler irrigated using irrigation cannons. There is no tailwater return system, but the field is bermed to contain treated effluent.

29. Five flow meters measure the volume of wastewater that is enters the WWTP and is treated and disposed. A summary of the meter numbers and measured wastewater sources is shown below. Flow meter locations are shown on Attachment C.

Flow Meters

Meter Description

Meter No. 1 Influent to the Headworks

Meter No. 2 Effluent from the Chlorine Contact Basin

Meter No. 3 Effluent Pond to Pond 4

Meter No. 4 Pond 4 to A-Street Pond

Meter No. 5 Pond 4 to Irrigation Field #1

30. The WWTP uses the SCADA system to monitor and control wastewater treatment plant processes, the pumps at Pond 4, water levels at the A-Street Pond, and the irrigation at Irrigation Field #1.

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31. The sewer collection system is old and significant storm water inflow and infiltration (I/I) into the sanitary sewer system is on-going. Several projects over the past few years have been conducted to remedy I/I. All of the main sewer lines have been close circuit televised (CCTV) and repairs have been made using trenchless technology to line the interior of the pipes. New lift stations were constructed in 2017 which allowed the Base to abandon several creek crossings and old sewer lines. Additional studies and remedies for I/I are on-going.

Planned Changes in the Facility and Discharge

32. Construction of an additional irrigation field (Irrigation Field #2) was completed in September 2011 but was never put into use. This irrigation field is comprised of two separate areas, as shown on Attachment B. The eastern field consists of 39 acres and uses spray cannons for irrigation. The western field of Irrigation Field #2 is comprised of 20 acres and has two spray cannons. Both fields are bermed to contain the wastewater on the fields. Vegetation on the fields consists of native and non-native invasive weeds, which are not non-edible and are not harvested for human consumption. Discharges to Irrigation Field #2 are regulated under this Order and a flow meter is required to be installed prior the use of the field.

33. The Discharger plans on utilizing small animals (goats or sheep) as a measure for vegetation control for the irrigation fields.

34. There are two existing ponds, Ponds 2 and 3, that have been constructed but have not been used. Both ponds are unlined and bermed. Ponds 2 and 3 have capacities of 1.3 MG and

26.5 MG, respectively. If water levels in Pond 4 become a concern, such as insufficient freeboard in Pond 4, wastewater from Pond 4 can be diverted and pumped to Ponds 2 and 3 for temporary storage. Once the water level in Pond 4 subsides, the water from Ponds 2 and 3 will gravity flow back to Pond 4. The Discharger has requested that Ponds 2 and 3 be added to this Order for use as a contingency measure in the event that 2 feet of freeboard cannot be maintained in Pond 4.

35. A project to enlarge A-Street Pond is also under consideration to allow discharges from the CG044-013 groundwater remediation system. Infrastructure is in place that would allow the effluent from the CG044-013 groundwater remediation system to discharge directly to the A- Street Pond, bypassing the effluent pond and Pond 4. Conveyance of CG044-013 effluent directly to A-Street Pond will not affect water quality as the Site CG044-013 effluent is proven to be of a higher quality than Title 22 disinfected secondary-23 recycled water standards. The amount of increased storage capacity has not been determined due to some constraints regarding existing vernal pools in the vicinity. Additional evaluations may be conducted.

Industrial Discharge Pretreatment

36. Industrial discharges to publicly owned wastewater treatment facilities (WWTFs) can cause one or more of the following problems if not adequately controlled:

a. Interference or Upset. Discharges of high volumes or concentrations of certain pollutants can inhibit or interfere with the proper operation of the WWTF, causing it to do an inadequate job of treating wastes. As a result, the facility could be prevented from meeting its permit requirements.

b. Sludge Management. Industrial pollutants, particularly metals and other toxic pollutants, can limit the sludge management alternatives available to the Discharger and increase the cost of sludge management and disposal. Additionally, biosolids contaminated with toxic pollutants could be rendered unsuitable as a soil amendment.

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c. Pass-through. Some industrial pollutants may not receive adequate treatment and pass through the treatment system at concentrations that can could unreasonably degrade groundwater quality and/or prevent recycling of domestic wastewater.

Additionally, the discharge of explosive, reactive, or corrosive wastes can cause damage to the wastewater collection system or the treatment works and may also pose a threat to worker or public safety.

37. The Discharger has implemented an industrial pretreatment program to regulate the discharge of industrial wastes into the wastewater collection system or treatment works to prevent damage to the sewer system or treatment works, inhibit or disrupt the treatment process, or cause violation of the effluent or groundwater limits of this Order. As part of the Discharger’s industrial pre-treatment program, sampling was conducted for six consecutive months beginning in October 2016. The samples were taken from the Secondary Clarifier as 24-hour composite samples. No constituent concentrations exceeded the effluent limits in the existing WDRs for the WWTP effluent. The complete analytical data set was included in the 2018 RWD. This Order contains provisions that require the Discharger continue to implement the program, periodically review and update the program as appropriate, and report any proposed new industrial discharges.

Site-Specific Conditions

38. The surrounding land use around Beale AFB is primarily agricultural. Surface water drainage in the area is to Hutchinson Creek, which eventually discharges to Bear River.

39. In the western portion of the Base, the area consists of relatively flat grassland. The plains transition eastward into low, rolling hills that gradually merge with the foothills of the Sierra Nevada. Elevations range from 80 to 90 feet above mean sea level (amsl) along the western and southwestern boundaries and is more than 400 feet amsl at the northeastern boundary.

40. The majority of the Base consists of low alluvial plains and former stream floodplains and channels, which has deposited sands, gravels, silt, and clay over time. Foothills of the Sierra Nevada are present in the eastern portion of the Base and the topography becomes progressively steeper and outcrops expose mostly older consolidated sedimentary rocks.

Some igneous and metamorphic crystalline basement rock of the Sierra Nevada is exposed near the eastern boundary.

41. The 100-year return period total annual precipitation value for Beale AFB is 39.33 inches. The average evapotranspiration rate is approximately 57 inches annually.

Groundwater Conditions

42. Groundwater under Beale AFB flows mainly through alluvial deposits, consisting of sediments deposited by water in stream beds, flood plains, lakes, and alluvial fans. Alluvial fans are characterized by heterogeneous particle sizes and distribution, resulting in highly variable hydraulic properties. Because of the complexity of the alluvial deposits, local aquifers are not clearly defined.

43. Groundwater beneath Pond 4 and Irrigation Field #1 ranges between 15 feet to 33 feet below groundwater surface (bgs). Near the A-Street pond and the Golf Course, depth to groundwater ranges from 27 feet to 33 feet bgs. The basewide downgradient flow direction

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is southwest but is more westerly in the southwest portion of the Base. Localized flow directions can vary due to pumping of groundwater for domestic use and groundwater remediation projects. Based on the Second Quarter 2018 Groundwater monitoring report, groundwater flows southwest near Pond 4, but flows northeast near the A-Street Pond and Golf Course.

44. Fourteen groundwater monitoring wells are used to monitor shallow groundwater quality near Pond 4, Irrigation Field #1, and the A-Street Pond. Well construction details are included in the Information Sheet and well locations are shown on Attachments D and E, incorporated herein.

45. Ten monitoring wells (P4C001MW to P4C009MW and background well BGL003MW) are used to evaluate groundwater quality at Pond 4. Monitoring well BGL003MW was identified as a background well for Pond 4 and the A-Street pond and is located 1.2 miles east of Pond 4 and 1.7 miles south of A-Street pond. This well is located in area unlikely to be influenced by infiltration from the ponds or other potential sources of contamination.

Analytical data for the Pond 4 monitoring wells are summarized below.

Groundwater Quality in Upgradient Monitoring Wells near Pond 4 1

BGL003MW 2 P4C001MW P4C002MW P4C003MW P4C007MW 3

Constituent (mg/L) avg max avg max avg max avg max avg max

TDS 152 176 291 385 107 137 139 238 219 280

Nitrate as N 3.2 4.7 3.7 5.6 2.4 3.31 3.4 4.22 6.7 8.7

TKN 0.4 0.9 0.5 2.3 0.2 1 0.3 1.1 0.7 4

Ammonia 0.2 0.7 0.2 1.5 0.2 0.6 0.2 0.4 0.6 3.4

Chloride 6.9 12.2 52.9 111 1.6 2.1 8.4 31.5 11.9 13.8

Sodium 9.6 16 14.2 16.9 6.6 7.4 7.84 9.1 15.7 40.7

Iron 4 0.02 0.18 0.07 0.28 0.12 0.32 0.49 0.99 0.14 1.04

Manganese 4 0.0003 0.0006 0.004 0.02 0.002 0.01 0.006 0.02 0.08 0.35

Total Coliform 5 (MPN/100mL)

BGL003MW 2 P4C001MW P4C002MW P4C003MW P4C007MW

2015 <2 8 22 30 17

2016 <2 <2 140 <2 130

2017 60 8 17 <2 <2

2018 <2 170 2 <2 <2 Concentrations in bold exceed a concentration protective of beneficial use.

Iron = 0.3 mg/L (Secondary Maximum Contaminant Recommended Level) Manganese = 0.05 mg/L (Secondary Maximum Contaminant Recommended Level)

1 Groundwater data from 2015-2017 and two quarters from 2018.

2 Background well 3 Cross gradient well 4 Total iron and total manganese 5 Maximum concentrations of total coliform reported for each year are shown.

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Groundwater Quality in Downgradient Monitoring Wells near Pond 4 1

P4C004MW P4C005MW P4C006MW P4C008MW P4C009MW

Constituent (mg/L) avg max avg max avg max avg max avg max

TDS 327 374 275 375 207 272 345 380 142 203

Nitrate as N 0.6 1.7 1.75 7.43 1.4 3.8 1.6 2.5 0.4 1

TKN 0.2 0.6 0.3 0.7 0.3 0.8 0.6 5 0.3 0.7

Ammonia 0.1 0.2 0.3 0.8 0.1 0.2 0.2 0.9 0.1 0.6

Chloride 58 71.4 62.3 99.4 45 97.9 66.7 81.7 5.6 7.1

Sodium 18.9 25.5 32 42.2 25.7 40.5 13 15.6 11.4 14.5

Iron 2 0.10 1.01 0.005 0.005 0.07 0.28 0.20 1.61 0.17 1.61

Manganese 2 0.004 0.01 0.05 0.20 0.0005 0.001 0.03 0.38 0.008 0.07

Total Coliform 3 (MPN/100mL)

P4C004MW P4C005MW P4C006MW P4C008MW P4C009MW

2015 <2 17 13 2 30

2016 <2 2 8 30 <2

2017 2 8 1600 2 <2

2018 <2 4 14 2 <2 Concentrations in bold exceed a concentration protective of beneficial use.

Iron = 0.3 mg/L (Secondary Maximum Contaminant Recommended Level) Manganese = 0.05 mg/L (Secondary Maximum Contaminant Recommended Level)

1 Groundwater data from 2015-2017 and two quarters from 2018.

2 Total iron and total manganese 3 Maximum concentrations of total coliform reported for each year are shown.

46. Concentrations of total manganese and iron exceed the concentrations protective of beneficial uses in upgradient wells P4C002MW and P4C003MW and cross gradient well

P4C007MW.

47. Concentrations of all constituents in monitoring wells downgradient of Pond 4 are less than concentrations protective of beneficial uses, except for total manganese and total iron.

48. Concentrations of chloride, nitrate as nitrogen, and TDS in all monitoring wells near Pond 4, including background well BGL003MW, show either stable concentrations over time or decreasing trends. Groundwater samples were also analyzed for TKN and ammonia as nitrogen. When evaluated as components of total nitrogen, along with nitrate, concentrations of TKN and ammonia were than less than nitrate as nitrogen.

49. Four groundwater monitoring wells are used to monitor shallow groundwater quality in the vicinity of the A-Street Pond. Monitoring wells PA03 and PA04 were previously identified as downgradient wells; however, due to fluctuating groundwater flow directions, PA03 and PA04 are located upgradient of the pond as documented in the Second Quarter 2018 Groundwater Monitoring Report and shown on Attachment E. Because of the fluctuating groundwater flow directions, the four wells were each evaluated as a location potentially impacted from infiltration from the A-Street Pond instead of representing conditions upgradient and downgradient of the pond.

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Groundwater Quality in Monitoring Wells near the A-Street Pond 1

BGL003MW 2 PA01 PA02 PA03 PA04

Constituent (mg/L) avg max avg max avg max avg max avg max

TDS 152 176 181 234 171 242 193 220 289 344

Nitrate as N 3.2 4.7 1.7 2.4 3.1 3.6 3.7 4.1 1.1 1.25

TKN 0.4 0.9 0.3 0.9 0.3 0.9 0.4 1.7 0.3 1.8

Ammonia 0.2 0.7 0.2 0.9 0.1 0.2 0.2 0.5 0.1 0.2

Chloride 6.9 12.2 14 16.9 9.8 11.2 31.6 41.4 56.7 71.1

Sodium 9.6 16 32.8 38.3 18.6 22.9 14.3 15.9 15.8 18.4

Iron 3 0.02 0.18 0.41 0.88 1.28 3.26 0.26 0.99 0.36 2.22

Manganese 3 0.0003 0.0006 0.009 0.06 0.08 0.12 0.004 0.009 0.009 0.06

Total Coliform 4 (MPN/100mL)

BGL003MW 2 PA01 PA02 PA03 PA04

2015 <2 4 <2 4 8

2016 <2 <2 <2 <2 4

2017 60 4 <2 2 <2

2018 <2 <2 <2 <2 <2 Concentrations in bold exceed a concentration protective of beneficial use.

Iron = 0.3 mg/L (Secondary Maximum Contaminant Recommended Level) Manganese = 0.05 mg/L (Secondary Maximum Contaminant Recommended Level)

1 Groundwater data from 2015-2017 and two quarters from 2018 2 Background well 3 Total iron and total manganese 4 Maximum concentrations of total coliform reported for each year are shown.

50. Concentrations of nitrate as nitrogen, chloride, and TDS show stable or decreasing concentrations over time in data generally collected between 2009 and 2018, with the exception of chloride in PA02. Chloride concentrations show an increasing trend. However, since 2009, the maximum concentration was 12 mg/L, less than the concentration protective of beneficial use of 500 mg/L. In addition, the average chloride concentration of 6.9 mg/L in background well BGL003MW is the same as the average concentration in PA02.

51. Groundwater samples are analyzed for contaminants associated with the Site CG044-013 groundwater remediation treatment plant, which include total petroleum hydrocarbon as diesel (TPHD) and volatile organic compounds (VOCs). Since 2013, TPHD and VOCs have not been detected in groundwater from the shallow groundwater monitoring wells located near Pond 4 and the A-Street pond.

52. Between 2015 and the second quarter of 2018, total coliform concentrations have been detected in all monitoring wells, including background well BGL003MW.

Basin Plan, Beneficial Uses, and Regulatory Considerations

53. The Water Quality Control Plan for the Sacramento River and San Joaquin River Basins, Fourth Edition, revised June 2015 (hereafter Basin Plan) designates beneficial uses, establishes water quality objectives, contains implementation plans and policies for protecting waters of the basin, and incorporates by reference plans and policies adopted by the State Water Board. Pursuant to California Water Code section13263(a), waste

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discharge requirements must implement the Basin Plan.

54. Local drainage is to Hutchinson Creek, which discharges to Western Pacific Interceptor, and finally to Bear River. The beneficial uses of surface water, as stated in the Basin Plan, are municipal and domestic supply (MUN); agricultural supply (AGR); industrial power (POW); hydropower generation; water contact recreation (REC-1); non-contact water recreation (REC-2); warm freshwater habitat (WARM); cold freshwater habitat (COLD);

migration of aquatic organisms (MIGR); and spawning, reproduction, and/or early development (SPAWN).

55. The beneficial uses of underlying groundwater as set forth in the Basin Plan are municipal and domestic supply (MUN), agricultural supply (AGR), industrial service supply (IND) and industrial process supply (PROC).

56. The Basin Plan establishes narrative water quality objectives (WQOs) for chemical constituents, tastes and odors, and toxicity in groundwater. It also sets forth a numeric objective for total coliform organisms.

57. The Basin Plan’s numeric WQOs for bacteria requires that the most probable number

(MPN) of coliform organisms over any seven-day period shall be less than 2.2 per 100 mL in MUN groundwater.

58. The Basin Plan’s narrative WQOs for chemical constituents, at a minimum, require waters designated as domestic or municipal supply to meet the MCLs specified in Title 22 of the California Code of Regulations (hereafter Title 22). The Basin Plan recognizes that the Central Valley Water Board may apply limits more stringent than MCLs to ensure that waters do not contain chemical constituents in concentrations that adversely affect beneficial uses.

59. The narrative toxicity objective requires that groundwater be maintained free of toxic substances in concentrations that produce detrimental physiological responses in human, animal, plant, or aquatic life associated with designated beneficial uses.

60. Quantifying a narrative water quality objective requires a site-specific evaluation of those constituents that have the potential to impact water quality and beneficial uses. The Basin Plan states that when compliance with a narrative objective is required to protect specific beneficial uses, the Central Valley Water Board will, on a case-by-case basis, adopt numerical limitations in order to implement the narrative objective.

61. In the absence of specific numerical water quality limits, the Basin Plan methodology is to consider any relevant published criteria. General salt tolerance guidelines, such as Water Quality for Agriculture by Ayers and Westcot and similar references indicate that yield reductions in nearly all crops are not evident when irrigation water has an EC less than 700 μmhos/cm. There is, however, an eight- to ten-fold range in salt tolerance for agricultural crops and the appropriate salinity values to protect agriculture in the Central Valley are considered on a case-by-case basis. It is possible to achieve full yield potential with waters having EC up to 3,000 μmhos/cm if the proper leaching fraction is provided to maintain soil salinity within the tolerance of the crop.

62. The Central Valley Water Board adopted Basin Plan amendments incorporating new programs for addressing ongoing salt and nitrate accumulation in the Central Valley at its 31

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May 2018 Board Meeting. These programs, once effective, could change how the Central Valley Water Board permits discharges of salt and nitrate. For nitrate, dischargers that are unable to comply with stringent nitrate requirements will be required to take on alternate compliance approaches that involve providing replacement drinking water to persons whose drinking water is affected by nitrates. Dischargers could comply with the new nitrate program either individually or collectively with other dischargers. For salinity, dischargers that are unable to comply with stringent salinity requirements would instead need to meet performance-based requirements and participate in a basin-wide effort to develop a long-term salinity strategy for the Central Valley. This Order may be amended or modified to incorporate any newly-applicable requirements.

63. The stakeholder-led Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) initiative has been coordinating efforts to implement the new salt and nitrate management strategies. The Central Valley Water Board expects dischargers that may be affected by new salt and nitrate management policies to coordinate with the CV-SALTS initiative.

Antidegradation Analysis

64. State Water Resources Control Board Resolution 68-16 (“Policy with Respect to

Maintaining High Quality Waters of the State”) (hereafter Resolution 68-16) prohibits degradation of groundwater unless it has been shown that:

a. The degradation is consistent with the maximum benefit to the people of the state.

b. The degradation will not unreasonably affect present and anticipated future beneficial uses.

c. The degradation does not result in water quality less than that prescribed in state and regional policies, including violation of one or more water quality objectives, and

d. The discharger employs best practicable treatment or control (BPTC) to minimize degradation.

65. Degradation of groundwater by some of the typical waste constituents associated with discharges from a municipal wastewater utility, after effective source control, treatment, and control measures are implemented, is consistent with the maximum benefit to the people of the state. The technology, energy, water recycling, and waste management advantages of municipal utility service far exceed any benefits derived from reliance on numerous, concentrated individual wastewater systems, and the impact on water quality will be substantially less. The economic prosperity of valley communities and associated industry is of maximum benefit to the people of the State and provides sufficient justification for allowing the limited groundwater degradation that may occur pursuant to this Order.

66. The Discharger has been monitoring groundwater quality at the site since 1996. Based on the data available, it is not possible to determine pre-1968 groundwater quality. Therefore, determination of compliance with Resolution 68-16 for this facility must be based on existing background groundwater quality.

67. The following constituents of concern have the potential to degrade groundwater as discussed below.

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Constituent

Average Concentrations (mg/L)

Effluent 1 Background

Groundwater 2

Downgradient Groundwater near Pond 4 3

Groundwater near A-Street

Pond 4

Concentrations Protective of

Beneficial Uses

TDS 442 146 266 209 1,000 5

Nitrate Nitrogen

13.51 3.2 1.2 2.4 10 6

Ammonia Nitrogen NA 0.19 0.18 0.15 --

TKN 6.15 0.36 0.36 0.32 --

Total Nitrogen

19.87 NA NA NA --

Sodium NA 9.6 25.5 19.9 69 7

Chloride NA 6.9 49.6 28.3 500 8

Total Iron NA 0.02 0.12 0.59 0.3 9

Total Manganese

NA 0.0003 0.02 0.02 0.05 9

Notes:

Half the reporting limit was used for non-detects for averaging purposes.

Concentrations in bold exceed the concentration protective of beneficial uses.

NA = not analyzed -- = not established

1 Flow weighted average from 2014-2017.

2 Results from BGL003MW from 2015-2017 and the first two quarters of 2018.

3 Results include data from 2015-2017 and the first two quarters of 2018 for monitoring wells P4C004MW-

P4C006MW, P4C008MW, and P4C009MW.

4 Results include data from 2015-2017 and the first two quarter of 2018 for monitoring wells PA01-PA04.

5 Secondary Maximum Contaminant Upper Level.

6 Primary Maximum Contaminant Level.

7 Agricultural Water Quality Goals, Taste and Odor Threshold 8 Secondary Maximum Contaminant Upper Level.

9 Secondary Maximum Contaminant Level.

a. Total Dissolved Solids. TDS concentrations in the effluent are greater than concentrations in shallow groundwater monitoring wells associated with Pond 4 and the A-Street Pond. In 2017, TDS was reported in domestic well water at a concentration of 241 mg/L, which is relatively equivalent to concentrations reported in the shallow groundwater monitoring wells.

The domestic well field is located approximately 4 miles northwest of Pond 4 and would not likely be influenced by discharges to Pond 4, the irrigation field, or the A-Street Pond. Based on TDS concentrations in effluent, shallow groundwater near the ponds, and TDS concentrations in domestic wells in the area, it does not appear the discharge is impacting groundwater with respect to TDS. TDS concentration trends are either stable or decreasing in the groundwater monitoring wells. This Order requires continued groundwater monitoring and does not allow an exceedance of the concentration protective of beneficial use.

b. Nitrate. For nutrients such as nitrate, the potential for degradation depends not only on the quality of the treated effluent, but the ability of the vadose zone below the effluent disposal ponds to provide an environment conducive to nitrification and denitrification to convert the effluent nitrogen to nitrate and the nitrate to nitrogen gas before it reaches the water table.

The effluent nitrate nitrogen concentration currently averages 13.5 mg/L and the background groundwater concentration averages 3.2 mg/L. In shallow groundwater monitoring wells

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around Pond 4 and the A-Street Pond, nitrate as nitrogen concentrations are less than background. This Order requires continued groundwater monitoring and does not allow an exceedance of the concentration protective of beneficial use for nitrate as nitrogen in groundwater.

c. Total Coliform Organisms. For coliform organisms, the potential for exceedance of the Basin Plan’s numeric water quality objective depends on the ability of vadose zone soils below the effluent storage/disposal ponds and saturated soils within the shallow water bearing zone to provide adequate filtration. Between 2015 and the second quarter of 2018, median concentration of total coliform has been less than 23 MPN/100mL for seven days but has exceeded 240 MPN/100mL in more than one sample in for the 30-day period requirement. These exceedances have likely resulted in groundwater impacts as total coliform have been detected in background well BGL003MW. This Order requires continued monitoring of groundwater and includes an effluent limit and groundwater limit for total coliform. This Order does not allow a total coliform exceedance of the Title 22 disinfected secondary-23 recycled water standards.

68. This Order establishes effluent and groundwater limitations for the WWTP that will not unreasonably threaten present and anticipated beneficial uses or result in groundwater quality that exceeds water quality objectives set forth in the Basin Plan.

a. For nitrate as nitrogen and TDS, current groundwater monitoring data indicate that groundwater has not been degraded beyond background groundwater quality by the discharge. The requirements of this Order do not allow an exceedance of concentrations protective of beneficial use.

b. For total coliform, current groundwater monitoring data indicates that the discharge has caused (or contributed to) exceedance of the concentration protective of beneficial use.

The provisions of this Order require that the Discharger implement BPTCs and includes a time schedule to bring the discharge into compliance with concentrations protective of beneficial use.

69. The Discharger provides treatment and control of the discharge that incorporates:

a. On-going collection system improvements to reduce and limit inflow and infiltration;

b. A Supervisory Control and Data Acquisition (SCADA) system for early detection of potential wastewater and treatment disruptions;

c. Wastewater treatment plant that provides secondary treatment with chlorine disinfection;

d. Fully contained treatment vessels, lined effluent pond, and concrete lined solids drying beds; and

e. Spray irrigation applied at agronomic loading rates for water and nutrients to minimize groundwater quality degradation.

Other Regulatory Considerations

70. Pursuant to Water Code section 106.3, subdivision (a), it is “the established policy of the state that every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes.” Although this Order is not necessarily subject to Water Code section 106.3 because it does not revise, adopt or

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establish a policy, regulation or grant criterion (see § 106.3, subd. (b)), it nevertheless promotes that policy by requiring discharges to meet MCLs designed to protect human health and ensure that water is safe for domestic use.

71. For the purposes of this Order, the WWTP is classified as “2B,” which denotes as follows:

Threat to Water Quality—Category 2 “Those discharges of waste that could impair the designated beneficial uses of the receiving water, cause short-term violations of water quality objectives, cause secondary drinking water standards to be violated, or cause a nuisance.”

Complexity—Category B “Any discharger not included [as Category A] that has physical, chemical, or biological treatment systems (except for septic systems with subsurface disposal) or any Class 2 or Class 3 waste management units.”

72. The discharges of waste authorized under this Order, and the associated operation of treatment ponds (as described herein), are exempt from the prescriptive requirements set forth in California Code of Regulations, title 27, section 20000 et seq. (See Cal. Code Regs., tit. 27, § 20090, subd. (a)-(b).)

73. Statistical data analysis methods outlined in the U.S. Environmental Protection Agency’s Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities, Unified Guidance (Unified Guidance) are appropriate for determining compliance with Groundwater Limitations of this Order. Depending on the circumstances, other methods may also be appropriate.

74. Beale AFB is covered under the Statewide General Permit for Storm Water Discharges Associated with Industrial Activities, State Water Board Order 2014-0057-DWQ, NPDES Permit No. CAS000001 (Industrial General Permit).

75. Water Code section 13267, subdivision (b)(1) provides as follows:

In conducting an investigation … the regional board may require that any person who has discharged, discharges, or … proposes to discharge … shall furnish, under penalty of perjury, technical or monitoring program reports which the board requires. The burden, including costs of these reports, shall bear a reasonable relationship to the need for the reports and the benefits to be obtained from the reports. In requiring those reports, the regional board shall provide the person with a written explanation with regard to the need for the reports, and shall identify the evidence that supports requiring that person to provide the reports.

76. Technical reports required under this Order (and per the separately-issued Monitoring and Reporting Program Order No. R5-2019-XXXX) are necessary to ensure compliance with the WDRs prescribed herein. Additionally, the burden of producing such reports, as estimated by Central Valley Water Board staff, is also reasonably related to the need for such reports.

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77. Absent promulgation of stricter standards pursuant to Water Code section 13801, Department of Water Resources’ standards for the construction and destruction of groundwater wells, per Bulletins 74-90 (June 1991) and 94-81 (Dec. 1981), shall apply to all wells installed or monitored in connection to this Order.

78. This Order does not authorize the disposal of biosolids generated by the WQCF.