TRVMP Final v4.pdf

INTERNATIONAL BOUNDARY AND WATER COMMISSION

UNITED STATES AND MEXICO

Tijuana River Valley Monitoring Plan (TRVMP)

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Introduction:

The International Boundary and Water Commission, United States and Mexico (IBWC), is responsible for applying the boundary and water treaties between the two countries and settling differences that arise in their application. The Commission consists of a U.S. Section and a Mexican Section, each part of its respective federal government.

The US Section (USIBWC) operates a 25-million gallon per day wastewater treatment plant, the South Bay International Wastewater Treatment Plant (SBIWTP), in San Diego, California in the San Ysidro Neighborhood adjacent to the Tijuana River and the US-Mexico border. The treatment plant treats wastewater that originates in Mexico and discharges the final effluent into the Pacific Ocean. Additionally, the USIBWC operates two canyon collectors that collect small transboundary flows from Smugglers and Goat Canyons and conveys the flows to the SIBIWTP. There are four other canyons located along the border that also have transboundary flows into the US that also can divert flows by gravity into the influent of the treatment plant.

The SBIWTP operates under a National Pollutant Discharge Elimination System (NPDES) permit issued by the San Diego office of the California Regional Water Quality Control Board (the Board). The current permit number CA0108928 was adopted on May 12, 2021 as Order No. R9-2021-0009 and amended on March 8, 2023 as Order No. R9-2023-0009. The order establishes the discharge limitations from the treatment plant as well as establishes the testing and reporting requirements to the Board. This includes the development and implementation of a routine testing program in the Tijuana River and associated canyons.

Per the amended order under Section 4.2 of Attachment E, the USIBWC is to develop and submit a monitoring plan for the Tijuana River Valley to the Board. The order details the base monitoring program with the potential to expand the program with collaboration from stakeholders under the IBWC Minute 320 program. The USIBWC currently holds an operations contract that maintains the treatment plant and compliance of the permit for the effluent. The USIBWC also currently holds a contract with the City of San Diego for the ocean monitoring program. This Tijuana River Valley Monitoring Program (TRVMP) details the implementation of the monitoring plan in accordance with the permit.

Objective:

The TRVMP is being conducted to provide information on the baseline concentrations in the transboundary flows entering the United States through the Tijuana River and adjacent canyons. Additionally, this data can also be used to determine impacts to the environment from transboundary flows due to infrastructure challenges resulting in discharge of untreated wastewater.

Project Leads:

The USIBWC will be responsible for the development of the program and all compliance and submission requirements to the Board. USIBWC will require the services of a private contractor to carry out this Monitoring program to include development of a QAPP to be approved by the USIBWC, sample collection, collection of field parameters, chain of custodies, shipment to a NELAC-accredited laboratory, and submission of the data from the field and the laboratory to the USIBWC.

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Sample collection:

Water and sediment samples will be collected at the monitoring sites listed in Table 1 per the frequency outlined below. Sample collection shall be conducted in accordance with an approved Quality Assurance Program Plan (QAPP). The QAPP will be developed by the contractor and provided for review and comment before sample collection will proceed. Sample collection protocols will follow industry standard sampling techniques. Examples of these procedures can be developed using the Arizona Department of Environmental Quality’s Manual of Procedures for the Sampling of Surface Waters and the United States Geological Survey’s National Field Manual for the Collection of Water-Quality Data.

Laboratory analysis:

Contractor will be responsible for shipping all samples to a NELAC-accredited laboratory managed under the Contractor. The Contractor will be responsible for providing a QAPP to the USIBWC and coordinating with the laboratory. All analysis will be conducted under an approved QAPP using methods approved by EPA or the Standard Methods for the Examination of Water and Wastewater, 24th edition. Recommended methods are provided in Tables 2 and 3 for the laboratory, however, the QAPP will contain the method used by the laboratory for the specified parameters.

Monitoring Sites:

The location of the proposed monitoring sites for this Program are shown in the Table 1 below.

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Table 1.

Monitoring Sites

Location Monitoring Matrix Monitoring

Location Name

Latitude Longitude

Sites on the Tijuana River:

1. Dairy Mart Bridge TRV-1 32° 32.9072' N 117° 3.867' W Water and Sediment

2. River Mouth TRV-7 32° 33.1362' N 117° 7.5677' W Water

Sites in the Transboundary Canyons and drains:

3. Stewart’s Drain Canyon Collector at the international boundary TRV-2 32° 32.4282' N 117° 3.4698' W Water and

Sediment

4. Canyon del Sol Collector at the international boundary TRV-3 32° 32.3502' N 117° 4.1197' W Water and Sediment

5. Silva Canyon Collector Drain at the international boundary TRV-4 32° 32.3677' N 117° 3.924' W Water and

Sediment

6. Smugglers Gulch 1 Diversion

Structure (near the international boundary line)

TRV-5 32° 32.388' N 117° 5.214' W Water and Sediment

7. Goat Canyon 1 Diversion Structure (near the international boundary line)

TRV-6 32° 32.22' N 117° 5.9587' W Water and Sediment

Water and/or sediment samples will be taken based on the monitoring frequency described below and in Table 2

Monitoring Description:

Water Sampling Water quality monitoring at the canyon collector monitoring locations (i.e., monitoring locations TRV-2 through TRV-6) is only required for Canyon Collector Transboundary Flow Events. Water quality monitoring is not required for transboundary flows that are diverted to the SBIWTP for treatment and discharge through the SBOO. Water quality monitoring samples will be collected at the canyon collectors for the parameters listed in Table 3 as follows: 1) once per Canyon Collector Transboundary Flow Event during dry weather; and 2) once per year during wet weather.

Monitoring during dry weather will be collected by collecting grab samples from: 1) a flowing water sample, and 2) a pooled or ponded water sample. A flowing water sample and a pooled water sample are separate samples. Monitoring during wet weather shall include: 1) a first flush grab sample if possible, and

2) a time-weighted composite sample during the event.

Samples shall be collected once per transboundary dry weather event that occurs at any of the canyon collector locations. As this is not a specified frequency, this sampling requirement has an unknown quantity and shall be listed as a separate line item with a per event cost. The contractor will be notified of the number of events that they are funded to perform and if that number of events is completed, the USIBWC will have to evaluate its capacity to fund

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Water quality monitoring at Dairy Mart Bridge and the Tijuana River mouth (i.e., monitoring locations TRV-1 and TRV-7, respectively) for the parameters listed in Table 4 will be conducted once per quarter during dry weather. Water quality samples will be collected when there is a transboundary flow event at

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Stewart’s Drain. If there are no transboundary flows at Stewart’s Drain during the quarterly monitoring period, samples will instead be collected when there is a transboundary flow at the Tijuana River main channel and once per year during wet weather. Monitoring during wet weather shall include: 1) a first flush grab sample if possible and 2) a sample collected during the event.

In addition, grab samples will be collected for E. coli and fecal coliform at Dairy Mart Bridge weekly by the USIBWC San Diego Field Office personnel and shipped to the contract lab. Contractor shall provide the SDFO with the supplies needed and shipping labels

For pesticides, polybrominated diphenyl ethers (PBDEs), and priority pollutants in Table 3 (except for volatile organic compounds), water samples should be analyzed for both dissolved phase (i.e., passing filters of 0.45 μm pore size) and suspended solid associated phase to adequately characterize pollutant concentrations in water samples.

Flow Measurements Flow measurements shall be taken during the sampling events for each location. For site TRV-1, the flow will be determined using the USIBWC gauge station location in the river channel upstream of Dairy Mart Bridge. For all other sites, flows will be estimated using visual means. The USIBWC is currently determining the ability to install continuous monitoring station at Smugglers Gulch and Goat Canyon and if installed will be used for the flow determination at those locations.

Sediment Sampling Sediment samples shall be collected in accordance with the methods developed for the Surface Water Ambient Monitoring Program (SWAMP) Stream Pollution Trends Monitoring Program (SPoT). Sediment samples for physical and chemical properties shall be taken concurrently with and adjacent to (as much as possible) the sediment samples for toxicity.

Sediment samples for assessment of sediment chemistry shall be collected twice per permit term at the canyon collector monitoring locations (i.e., monitoring locations TRV-2 through TRV-6) and the Dairy Mart Bridge monitoring location (i.e., monitoring location TRV-1) listed in Table E-1. Sampling shall be spaced equally throughout the permit term to the extent possible.

Sediment monitoring for physical and chemical properties shall be conducted at the Dairy Mart Bridge and canyon collector monitoring locations in Table 1 (i.e., monitoring locations TRV-1 through TRV-6) for the parameter groups identified in Table 4.

Sediment toxicity samples shall be collected in accordance with the methods used for SPoT. Sediment samples for toxicity and taken concurrently with the sediment samples for physical and chemical properties.

Sediment toxicity analyses will use the Hyalella aztexa 10-day survival and sublethal test (test method 100.1) in accordance with USEPA 600/R-99/064, Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates (2000).

Trash Sampling A trash assessment will be conducted once in year two and once in year four of the program at Smugglers Gulch and Goat Canyon (i.e., monitoring locations TRV-5 and TRV-6, respectively) after a wet weather event. The trash assessment method will be conducted as contained in A Rapid Trash Assessment Method Applied to Waters of the San Francisco Bay Region: Trash Measurement in Streams (SWAMP 2007) available on the California Regional Water Quality Control Board, San Francisco Region

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http://www.waterboards.ca.gov/sanfranciscobay/docs/swampthrashreport.pdf Trash assessments shall include an assessment of all trash, including waste tires.

http://www.waterboards.ca.gov/sanfranciscobay/docs/swampthrashreport.pdf

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Table 2. Summary of sample collection

Sampling Parameters Monitoring

Location Name

Monitoring Matrix

Frequency

Sites on the Tijuana River:

1. Fecal Coliforms and E.coli TRV-1 Water Weekly, to be collected by the

USIBWC FO

2. Table 3 parameters, dry weather

TRV1

and TRV-

Water quarterly

3. Table 3 parameters, wet weather

TRV1

and TRV water Once per year

4. Table 4 parameters TRV-1 Sediment 2x/Permit Term (year 2 and 4)

Sites in the Transboundary Canyons and drains:

5. Table 3 parameters, dry weather

TRV-2-6

Water:

1 from flow and 1 from pool

Once during a TB flow event

6. Table 3 parameters, wet weather TRV-2-6 Water: grab from first flush and a 24 hour composite

Once per year during wet weather event

7. Table 4 parameters TRV-2-6 Sediment 2x/Permit Term (Year 2 and 4)

8. Trash assessment TRV-5 and TRV-6 Trash 2x/Permit Term

(year 1 and 3) All samples are grab samples except the wet weather event which will be one first flush grab and a time-weighted composite.

Data Ownership:

The data and the results from this Monitoring Program will be the property of USIBWC, who will submit the data to the Board for compliance with the NPDES permit.

Quality Assurance Project Plan:

Development of a Quality Assurance Project Plan (QAPP) will be developed by the contractor and

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Figure 1. Tijuana River Valley Monitoring Locations.

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Water Quality Parameters:

Table 3

Parameter Group Units Recommended

Analytical Method [1]

Visual Observations [2] -- -- Flow Rate MGD Described above

Conductivity Micromhos per centimeter (μmhos/cm)

[3]

Temperature °F [3] pH Standard Units [3] Dissolved Oxygen mg/L [3] Turbidity NTU [3] TSS mg/L [4] [3] cBOD mg/L [4] [3] Ammonia (as N) mg/L [4] [3] Nitrogen, Total mg/L [4] [3] Phosphorus, Total (as P) mg/L [4] [3] E. coli [5] Number/100 mL [3] Enterococci [6] Number/100 mL [3] Fecal Coliform Number/100 mL [3] Norovirus and Enterovirus Number/100 mL USEPA 1615

Surfactants, Anionic, Methylene Blue Active Substances (MBAS) mg/L [4] SM5540C

Heavy Metals µg/L [4] USEPA 6010

Mercury (Total and Methyl) µg/L [4] USEPA 245.1 or

USEPA 7471

Organochlorine Pesticides µg/L [4] USEPA 8081B

Organophosphorus Pesticides µg/L [4] USEPA 8141

PAHs µg/L [4] USEPA 8270 PCB Congeners µg/L [4] USEPA 8082 Volatile Organic Compounds µg/L [4] USEPA 8260 Semi-volatile Organic Compounds µg/L [4] USEPA 8270 Pyrethroid Pesticides µg/L [4] USEPA 8081B Neonicotinoid Pesticides µg/L [4] ELISA/USEPA 625-

NCI

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Carbamate Pesticides µg/L [4] USEPA 632 PBDEs µg/L [4] USEPA 8081B Nonylphenols and Nonylphenol ethoxylates µg/L [4] [7] Total Cyanide µg/L [4] USEPA 335.4 2,3,7,8-TCDD µg/L [4] USEPA 613 Notes for Table 3

[1] Actual methods will be provided in the QAPP.

[2] Visual observations of the surface water conditions at the designated receiving water monitoring locations shall be conducted in such a manner as to enable the observer to describe and report the presence, if any, of floatables of sewage origin and trash. Observations of weather (cloudy, sunny, or rainy), tidal conditions (high or low; at applicable monitoring locations), water color, oil and grease, turbidity, and odor shall also be recorded. For canyon collector monitoring locations, the Discharger shall also observe if sediment is accumulating in the canyon collector system. These observations shall be taken whenever a sample is collected.

[3] Consistent with the methods prescribed under 40 CFR part 136.

[4] Mass emission rate (MER) of the constituent for each sample taken shall be calculated in accordance with section 7.12 of Order No R9-2023-0009.

[5] E. coli is required at freshwater monitoring locations (i.e., monitoring locations TRV-1 through TRV-6).

[6] Enterococci is required at saline monitoring locations (i.e., monitoring location TRV-7).

[7] The recommended analytical method is described in Method validation and reconnaissance of pharmaceuticals, personal care products, and alkylphenols in surface waters, sediments, and mussels in an urban estuary (Klosterhaus et al. 2013).

Sediment Parameters:

Table 4

Parameter Group [2] Units Type of Sample

Minimum Sampling Frequency

Recommended Analytical Method [1]

Sediment Grain Size μm

Grab

2/Permit Term [2]

USEPA/620/R-

95/008 or ASTM

D-442 Total Organic Carbon Percent Grab 2/Permit Term [2] USEPA 9060A Heavy Metals (Total) mg/kg Grab 2/Permit Term [2] USEPA 6020

Mercury (Total and Methyl) mg/kg Grab 2/Permit Term [2] USEPA 245.5 or

PAHs ng/g Grab 2/Permit Term [2]

USEPA 8270-

NCI Low Detection

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PCB Congeners ng/g Grab 2/Permit Term [2] USEPA 8082 Nonylphenols and Nonylphenol ethoxylates ng/g Grab 2/Permit Term [2] [3]

Organochlorine Pesticides ng/g Grab 2/Permit Term [2] USEPA 8081 Organophosphorus Pesticides ng/g Grab 2/Permit Term [2] USEPA 8141

Pyrethroid Pesticides ng/g

Grab

2/Permit Term [2]

USEPA 8270-

NCI Low

Detection or

USEPA

8081/1699 PBDEs ng/g Grab 2/Permit Term [2] USEPA 8081B Notes for Table 4

[1] Laboratory QAPP contains method used.

[2] Sampling shall be spaced equally throughout the permit term to the extent possible.

[3] The recommended analytical method is described in Method validation and reconnaissance of pharmaceuticals, personal care products, and alkylphenols in surface waters, sediments, and mussels in an urban estuary (Klosterhaus et al. 2013). The Discharger may recommend an alternative method if in concurrence with the San Diego Water Board.