Pacifica State Beach Special Study
Bacteria Water Quality Monitoring
Program
Prepared For City of Pacifica and County of San Mateo
By the San Mateo County Resource Conservation District
Sep 6, 2022
Contact: Noah Katz
Water Quality Program Manager
80 Stone Pine Rd, Suite 100
Half Moon Bay CA, 94019
(650) 712-7765 ext. 117
[email protected]
ATTACHMENT C
2 Table of Contents
I. Background ...............................................................................................................................................3 II. Program Objectives............................................................................................................................. 4 III. Watershed Information.................................................................................................................5 IV. Previous Studies .................................................................................................................................6 Pacifica State Beach.....................................................................................................................................6 San Pedro Creek: .............................................................................................................................................7 V. Scope of Work ..........................................................................................................................................7 Task 1: Program Administration............................................................................................................8 Task 2: Water Quality Sampling............................................................................................................8 Task 3: Data Management, Analysis and Reporting............................................................13 Task 4: Best Management Practice Recommendations – GIS Analysis ................13 VI. Project Timeline................................................................................................................................13 VII. Special Study Timeline.................................................................................................................14 VIII. Budget.....................................................................................................................................................14 3 I. Background
San Pedro Creek and Pacifica State Beach, in the City of Pacifica in San Mateo County, California and are on the Clean Water Act’s 303(d) list for impairment by fecal indicator bacteria (FIB). FIB (fecal coliform, total coliform, E. coli, and Enterococcus) are associated with the feces of warm-blooded animals (ex:
human, horse, dog, wildlife) and indicate the potential presence of pathogens that can cause adverse effects in humans (ex: gastroenteritis, skin rash, hepatitis, cholera, typhoid fever).
The San Francisco Bay Regional Water Quality Control Board (RWQCB) adopted the San Pedro Creek and Pacifica State Beach Bacteria Total Maximum Daily Load (TMDL) to address these impairments. The TMDL establishes Waste Load Allocations (WLA), or a number of permitted exceedances of water quality objectives (WQOs) that are designed to protect the water contact recreation beneficial use.
The TMDL required that WLAs for Pacifica State Beach be attained by August 1, 2021, and WLAs for San Pedro Creek be attained by August 1, 2028. WLAs for Pacifica State Beach were not met by the 2021 deadline. However, this appears to be the result of incorrect sample site locations rather than an indicator that pollution at the beach exceeds water quality objectives.
San Mateo County Environmental Health collects weekly samples at the creek mouth and at the beach within the mixing zone of the creek discharge (point zero). To assess attainment of WLAs, the TMDL required an additional monitoring site 300-feet north of the creek mouth be sampled weekly by the County. Unfortunately, for some time, compliance with WLAs at the beach was being assessed with data collected from point zero at the creek mouth 4 discharge (Linda Mar 5) as samples were not being collected from 300-feet north (Linda Mar 7). This issue has since been resolved and the County is now sampling all three locations (creek mouth, Linda Mar 5, and Linda Mar 7) both locations and exceedances of the water quality objective for enterococcus are far rarer at Linda Mar 7 than at Linda Mar 5.
These findings suggest two things: [1] WLAs for the beach may currently be in attainment; and [2] the primary source of bacteria to the beach is San Pedro Creek discharges. In addition to the creek mouth there are other potential source of bacterial pollution along the beach including restroom facilities, a restaurant, stormwater pumpstation overflows, pet waste, and marine life including seagulls, as well as from commercial facilities on the south end of the beach. In order to identify and quantify the potential impact of these sources on bacterial concentrations along the beach we must be able to determine when creek discharges are and are not impacting bacterial counts at discrete locations along the beach.
II. Program Objectives
This special study will assess the spatial and temporal extent of bacteria impairment at the beach. Water quality data collected under this effort aims to constrain bacteria sources and determine the safe to swim zone along the beach. Samples collected from monitoring locations at the creek mouth and distributed north and south along the beach will provide data to isolate bacterial sources and characterize the spatial extent of bacterial impairments along the beach
Grab samples will be collected at the established monitoring sites at the creek mouth, point zero at the mixing zone (LM5) and at designated intervals along the beach and analyzed for FIB. Salinity data will be collected with each 5 grab sample. Salinity measurements provide an additional water quality parameter that project team will evaluate to characterize the creek discharge plume and potential correlations with bacteria.
A separate section of this study will focus on assessing compliance with WLAs at Linda Mar 7. This section will analyze all available weekly sampling data at Linda Mar 7, Linda Mar 5, and the Creek Mouth to determine if WLAs are being met for the beach.
Finally, based on findings of the plume study and of the WLA Assessment, a stormwater best management practices (BMP) analysis using ArcGIS will be developed by the RCD. The objective of the BMP analysis is to identify stormwater BMPs in the watershed. If the plume study identifies significant sources of bacteria along the beach, BMPs will focus on those sources. If the plume study does not identify any significant sources of bacteria along the beach, then BMPs will focus on stormwater management opportunities in the upper watershed.
III. Watershed Information
San Pedro Creek is a perennial stream that flows from the Santa Cruz Mountains through San Pedro Valley and the City of Pacifica to its mouth at Pacifica State Beach. Precipitation varies from the headwaters to the mouth with approximately 38 inches per year in higher elevations and 23 inches per year in the lowest elevations. The creek drains approximately 8 square miles of residential, commercial, and open space areas. The mainstem of the creek is 2.5 miles long and about 36 percent of the creek is modified. About 33 percent of the watershed is developed and 15 percent of the watershed consists of impervious surface (STOPPP, 2002; Sassoubre, 2011). 6 The San Pedro Creek watershed is comprised of the mainstem of the creek, numerous catchments with perennial and intermittent tributaries, and spring water within the stormwater network. The Middle Fork, the South Fork, and the Sanchez Fork are open channel, perennial streams with vegetated banks. The Northeast and Northwest Forks consist of several perennial and intermittent tributaries that are conveyed into the stormwater system before discharging to the mainstem. The Shamrock catchment is comprised of intermittent open channel tributaries routed through ponds before being routed into the stormwater system and discharging to the mainstem. The Crespi catchment consists of perennial spring water within the stormwater system that is routed to an open concrete-lined channel that discharges to the mainstem. Anza and Linda Mar catchments do not drain to San Pedro Creek but rather to pump stations where stormwater is conveyed to Pacifica State Beach. The small remaining catchments in the watershed convey wet weather flows through the stormwater network to the mainstem of the creek.
IV. Previous Studies
Pacifica State Beach:
San Mateo County Public Health conducts weekly water quality sampling for FIB at Linda Mar 5 and Linda Mar 7 north of San Pedro Creek Mouth at Pacifica State Beach.
A study by Jennings et al., 2020 titled “Participatory science for coastal water quality: freshwater plume mapping and volunteer retention in a randomized informational intervention” used participatory science to collect shoreline data for including salinity along Pacifica State Beach to determine safe 7 swimming distances from San Pedro Creek Mouth. FIB samples were not included in this study. Based on salinity data and other factors, median safe swimming distance from San Pedro Creek mouth was determined to be 150m south and 100m north. Safe swimming distances were strongly associated with freshwater discharge rate and tide level.
San Pedro Creek:
San Pedro Creek has been monitored for fecal indictor bacteria at numerous locations and by a variety of organizations over the last two decades. Overall, results show that fecal bacteria can exceed WQOs for water contact recreation in both the wet and dry season, and in urban and non-urban areas, though exceedances from non-urban areas appear to be less common.
The RWQCB has identified controllable sources of bacteria in the San Pedro watershed as the sanitary sewer system, horse facilities, municipal stormwater runoff, and dry weather flows (RWQCB 2012). Wildlife (birds, raccoons, rodents, deer etc.) are also identified as sources but are not considered to be controllable. The TMDL can be referenced for more information on previous monitoring efforts and microbial source assessments.
V. Scope of Work
This document outlines the scope of work for monitoring from October 1, 2022, to September 31, 2023. The scope of work includes the following tasks:
• Program Administration
• Water Quality Monitoring
• Data Management, Analysis, and Reporting
8 Task 1: Program Administration
The RCD will implement all aspects of the program except for laboratory processing of the water samples. The program administration task involves program oversight, planning, and project management including drafting internal resources (i.e. checklists, maps), communicating with partners and stakeholders, and invoicing on a quarterly schedule.
Task 2: Water Quality Sampling
Figure 1. Special Study Monitoring Locations
Table 1. List of San Vicente Creek Bacteria Monitoring Site IDs, Names and Locations.
Site
#
Site
ID Site Name Site Location Analytes
1 NLM3
North of
Linda Mar
3 37°35'55.79"N
122°30'9.07"W
(~235 feet north of LM6)
Entero, MST, Salinity
2 LM6 Linda Mar
6 37°35'53.88"N
122°30'10.80"W
(~235 feet north of NLM2
Entero, MST, Salinity
9 Site
#
Site
ID Site Name Site Location Analytes
3 NLM2
North of
Linda Mar
2 37°35'52.31"N
122°30'13.00"W
(~235 feet north of NLM1)
Entero, MST, Salinity
4 NLM1
North of
Linda Mar
1 37°35'50.71"N
122°30'15.08"W
(~235 Ft N of Linda Mar 7)
Entero, MST, Salinity
5 LM7 Linda Mar
7 37°35'49.42"N
122°30'17.63"W
(~300 ft north of Linda Mar 5)
Entero, MST, Salinity
6 LM50-
N
50 Feet
North of
Linda Mar
5 37°35'47.83"N
122°30'20.44"W Entero, MST, Salinity
7 LM5 Linda Mar
5 37°35'47.57"N
122°30'20.93"W
Point Zero Sampling (AB411 Site)
Entero, MST, Salinity
8 LM5-
HD
Linda Mar
5 Hip
Depth
Hip Depth at LM5 instead of ankle depth Entero, MST, Salinity 9 SPCM
San Pedro
Creek
Mouth
37°35'46.62"N
122°30'19.77"W E.coli, MST, Salinity
10 LM50-
S
50 Feet
South of
Linda Mar
5 37°35'47.27"N
122°30'21.45"W Entero, MST, Salinity
11 SCM1
South of
Creek
Mouth 1
37°35'46.74"N
122°30'23.69"W
(~235ft S of Creek Mouth)
Entero, MST, Salinity
12 SCM2
South of
Creek
Mouth 2
37°35'46.07"N
122°30'26.45"W
(~235 feet south of SCM1)
Entero, MST, Salinity
RCD staff will collect bacteria samples and salinity measurements at 12 locations (see Table 1) including San Pedro Creek Mouth, Linda Mar 5, Linda Mar 6, and Linda Mar 7, as well as from sites extending approximately 1,200 feet north, and 600 feet south of the creek mouth. Bacteria samples collected from the creek mouth will be analyzed for E. coli. Samples from all marine 10 sites will be analyzed for enterococcus. E. Coli Samples will be analyzed against the water quality objective (WQO) from the San Francisco Bay Basin Plan for water contact recreation for fresh waters (<320 MNP/100 mL).
Enterococcus samples will be analyzed against the WQO from the Basin Plan’s numeric objectives for water contact recreation in ocean waters (110 MPN/100 mL).
RCD staff will collect water quality samples approximately monthly during seven wet weather events and five dry weather events. During wet weather events, RCD staff will sample any stormwater outfalls and distinct drainages along the beach where possible to isolate potential source of FIB relating to stormwater discharge.
RCD staff will collect MST samples at all sites, during at least two wet and two dry events. These samples will be filtered and preserved by the lab for selective analyses based on the FIB data collected on the same dates as the MST samples. FIB WQOs will be used as MST analysis thresholds. MST samples for FIB exceedances of WQOs will be analyzed for the following markers: human, horse, dog, seagull, and universal.
Wet weather events for this program are defined as at least 0.10 inch of precipitation in <24 hours to capture the effects of stormwater runoff into the creek. RCD staff will track weather using online weather databases (ex:
Wunderground) and a rainfall gage in Montara
(http://www.balancehydrologics.com/mwsd/). RCD staff will collect samples as soon as possible after a wet weather event but no longer than 72 hours following the event so that the effects of precipitation can still be captured.
Staff will collect dry weather samples between May and September. 11 RCD staff will collect all water samples using standard protocols and sampling methods that comply with the State of California’s Surface Water Ambient Monitoring Program (SWAMP) for Sampling and Analysis of Indicator Bacteria in Fresh Water. RCD staff will collect samples in factorysealed, pre-sterilized, plastic bottles (100/125 mL) without preservative and new sampling gloves will be worn at each site. When possible, water samples will be collected directly into the sample container. If a sampling device such as a bucket is necessary to collect samples, the sampling device will be rinsed with isopropyl alcohol followed by distilled water prior to and in between sampling locations and rinsed in the sample water three times. The sampling device will also be soaked in a 10% bleach solution for 30 minutes prior to each sampling event. Samples will be put directly on ice (<10 °C) and delivered to the Cel Analytical Laboratory under Chain of Custody within 6 hours of sample collection. Whenever possible, samples will be delivered to the lab Monday through Thursday before 1 pm to avoid after hours fees. Cel Analytical Laboratory is an ELAP certified laboratory and will quantify FIB using the Quantitray method. Salinity will be measured at each site using a multi-probe water quality meter (YSI).
For quality assurance and control (QA/QC), the RCD will collect a field duplicate, and a field blank for all FIB constituents during each sampling event. For Bacteroidales QAQC, a duplicate will be collected during each sampling event and will be analyzed for all markers and a blank will be analyzed for the universal marker. A matrix spike sample will also be collected once during the dry season and once during the wet season and analyzed for the Universal Marker. A field duplicate will be collected using a single 250-mL sampling container which the lab will split into duplicate samples. This method was chosen to minimize variation between duplicate samples. A field blank will be collected by directly filling a laboratory bottle with distilled 12 water at one of the sampling sites. If an intermediate container is used, an instrument blank will be collected by following the bucket cleaning protocol and deionized water will be poured into the contained and then into a 100- mL bacteria sample bottle.
For field salinity measurements, RCD will use a YSI Field Probe which will be calibrated using conductivity calibration solution for marine waters before each sampling event and a duplicate salinity measurement will be recorded once during each sampling event.
During each sampling event, RCD will collect flow data at the creek mouth using a Global Water Flow Meter. Note that when flow is insufficient to use the flow meter, RCD staff will estimate flow visually. Supplementary information such as observations, weather, time, date, flow rate (freshwater samples), and tidal information will be recorded on a field datasheet.
Adaptive Management
• To further assist in isolating the lateral extent of freshwater pollution at the beach, sample sites have been included at 50-feet north and south of the creek mouth. The location of these sampling sites will be adaptively managed based on bacterial sample results to identify safe swimming distance. For example, the sample sites at 50-feet north and south of the creek mouth will be moved further away from the creek mouth should FIB concentrations exceed the WQO at the 50-foot location established in this proposal.
• MST samples will be collected during at least two wet and two dry season events and analyzed selectively (retroactively) based on FIB data.
13 • As proposed above, wet season sampling events will be carried out approximately monthly following 0.10-inches of rain. If rain does not fall within any wet season month (Oct-Apr) then samples will be collected for a winter dry event.
Task 3: Data Management, Analysis and Reporting
RCD staff will review results from the laboratory for completeness, errors and red flags. The RCD will organize and manage this data electronically and assess results against the e. coli WQO (<320 MPN/100 mL) and Enterococcus WQO (<110 MPN/100 mL). Data will be displayed in a variety of ways (graphs, tables, maps etc.) for the best visual representation.
The RCD will submit an annual report to the County and City of Pacifica by February 15, 2024 and to the Regional Board by March 15, 2024. This report will be provided in time for submittal of the County’s annual Municipal Regional Permit Report to the RWQCB. RCD annual reports will include analysis of monitoring results, characterization of sources, in addition to BMP recommendations.
Task 4: Best Management Practice Recommendations – GIS Analysis Analysis of water quality data and identification of bacteria sources will highlight appropriate remediation measures and solutions. The RCD will use information from analysis of current and historical data to scope appropriate BMPs for reducing bacterial concentrations for discrete sources along the Pacifica State Beach.
VI. Project Timeline
Water Year Month/Calendar Year Timetable
2023
Oct, 2022
Wet Season Sampling
Nov, 2022
14 Dec, 2022
Jan, 2023
Feb, 2023
Mar, 2023
Apr, 2023
May, 2023
Dry Season Sampling
Jun, 2023
July, 2023
Aug, 2023
Sep, 2023
2024
2024
Oct, 2023
Nov, 2023 Data analysis and Reporting Period
Dec, 2023
Jan, 2024 RCD Internal Review Jan 31, 2024
Feb, 2024 Submit Draft to City of Pacifica and the County Feb 1, 2024 Mar, 2024 Special Study Report Due to Regional Board (Mar 15, 2024) Apr, 2024
May, 2024 Final Report review period
Jun, 2024
VII. Special Study Timeline
• October 1, 2022: Begin special study sampling program • October 1, 2023: Begin data Analysis and reporting period • Feb 1, 2024: Submit draft report to the County and City of Pacifica • March 15, 2024: Submit draft to Regional Board
• June 15, 2024: Submit reporting on any newly identified and proposed BMPs
VIII. Budget
The estimated total cost of this project including reporting for the special study is approximately $130,000 to be split between the City of Pacifica and the County of San Mateo Office of Sustainability. A budget is provided below. 15 Task 1. Program Administration Qty Rate Amount
Executive Director - Program Oversight 21 $209 $4,398.9 Administrative Officer - Invoicing, budget tracking etc. 11 $109 $1,146.1 Water Quality Program Manager- site visits, communication, planning, project management etc. 105 $90 $9,468.9 Water Quality Project Manager- site visits, communication, planning, project management etc. 35 $81 $2,834.0 Water Quality Program Coordinator- site visits, communication, planning, project management etc. 35 $70 $2,447.2 $20,295.0
Task 2. Water Sampling Qty Rate Amount
Water Quality Program Manager- Sampling event prep, driving, grab samples, lab delivery 30 $90 $2,705.4 Water Quality Project Manager- Sampling event prep, driving, grab samples, lab delivery 10 $81 $809.7 Water Quality Program Coordinator - Sampling event prep, instrument calibration, driving, grab samples, lab delivery120 $70 $8,390.4 Conservation Project Coordinator - Sampling event prep etc. 96 $58 $5,557.4 Sampling Supplies (ice, gloves, mileage, YSI calibration solution, etc) 2 $1,000 $2,000.0 Mileage 12 $38 $450.0
Cel Analytical Lab Fees Cost Estimate + 5k buffer 1 $58,110 $58,110.0 YSI Annual Maintenance 1 $1,000 $1,000.0
$79,022.9
Task 3. Data Management, Analysis and Reporting Qty Rate Amount Water Quality Program Manager 200 $90 $18,036.0 Water Quality Project Manager 85 $81 $6,882.5 Water Quality Program Coordinator 100 $70 $6,992.0 GIS Consultant 1 $5,000 $5,000.0
Task 3 Total $36,910.5
$136,228.4
Pacifica State Beach Special Study (Sampling Oct 2022 - Sep 2023) Task 1 Total
Task 2 Total
Project Total