Embed Size (px)
Citation preview
Memorandum
D A T E:
Daniel le Potocek, Ph.D.
Ashl i Cooper-Desai
Amir Mani , Ph.D.
720 Wilshire Boulevard, Suite 240
Santa Monica, CA 90401
310.394.1036
Karen Ashby
1480 Drew Avenue, Suite 100
Davis, CA 95618
530.753.6400
July 28, 2017
T O: Lewis Michaelson, Katz and Associates
Steve Weisberg, Southern California
Coastal Water Research Project
S U BJ E C T: Orange County - Enclosed Bays and
Estuaries Analysis
Cc:
I. PURPOSE
At the March 30, 2017, Newport Bay Fecal Coliform Total Maximum Daily Load (TMDL)
stakeholder group meeting, Larry Walker Associates (LWA) was asked to conduct a reference
bay analysis by completing the following:
Identify the Southern California enclosed bays and estuaries (EBE) for use in the
analysis;
Obtain the available enterococcus data from the identified EBE (2010-2016); first
available AB411 data and then other, additional, available data;
Analyze the AB411 data, categorized by dry and wet weather, to determine the
distribution of exceedances within the selected waterbodies; and
Determine if additional data should be added to the AB411 dataset and re-analyzed.
A similar wet and dry enterococcus analysis is being conducted by County of Orange staff for
Upper and Lower Newport Bay. Therefore, this waterbody was not included in this analysis.
The primary purpose of this analysis is to determine if there are waterbodies in Southern
California that may serve as reference sites for Newport Bay. The details of the analysis are
provided below.
II. IDENTIFICATION OF SOUTHERN CALIFORNIA ENCLOSED BAYS AND ESTUARIES
Definitions
The following definitions were generally used to identify potential waterbodies.
Page 2
EBE Reference Site Analysis
Enclosed Bays1: indentations along the coast which enclose an area of oceanic water within
distinct headlands or harbor works. Enclosed bays include all bays where the narrowest distance
between headlands or outermost harbor works is less than 75 percent of the greatest dimension of
the enclosed portion of the bay.
Estuary2: Region of interaction between rivers and near-shore ocean waters, where tidal action
and river flow mix fresh and salt water. Such areas include bays, mouths of rivers, salt marshes,
and lagoons.
Estuaries and Coastal Lagoons2: waters at the mouths of streams that serve as mixing zones for
fresh and ocean waters during a major portion of the year. Mouths of streams that are
temporarily separated from the ocean by sandbars shall be considered as estuaries. Estuarine
waters will generally be considered to extend from a bay or the open ocean to the upstream limit
of tidal action but may be considered to extend seaward if significant mixing of fresh and salt
water occurs in the open coastal waters.
EBE Identification
Satellite imagery from Google Earth was used to identify sites within Ventura, Los Angeles,
Orange, and San Diego counties which might qualify as an EBE. The initial search was
intentionally inclusive and resulted in a total of 36 possible sites. The sites were classified into
three tiers based on a visual inspection of satellite imagery:
Tier 1: Enclosed Bay (N = 14)
Tier 2: Lagoon/Estuary (N= 9)
Tier 3: River or Creek Mouth (N= 13)
The initial list included enclosed bays, lagoon/estuaries, as well as rivers and creeks entering the
ocean which can form temporary berms resulting in small back estuaries. After consulting with
Steve Weisberg of Southern California Coastal Water Research Project (SCCWRP) it was
determined that the analysis would only include the Tier 1 sites, which were most similar to
Newport Bay and offered the best data coverage. Tier 1 sites included 14 unique waterbodies
shown in Table 1 below.
1 State Water Resources Control Board – Water Quality Control Plan for Enclosed Bays and Estuaries – Part 1
Sediment Quality - http://www.swrcb.ca.gov/water_issues/programs/bptcp/docs/sediment/sed_qlty_part1.pdf 2 State Water Resources Control Board – Glossary and Definitions of Water Words
http://www.waterboards.ca.gov/publications_forms/available_documents/water_words/words_e.pdf
Page 3
EBE Reference Site Analysis
Table 1. Southern California Tier 1 Waterbodies.
AB411 Station Locations
AB411 requires that the local counties test the waters adjacent to all public beaches receiving at
least 50,000 visitors a year for microbial contamination in order to protect the health of
swimmers and surfers3. The Heal the Bay Report Card4 collates AB411 data and assigns each
beach a grade based on the risk of adverse health effects to swimmers and surfers.
Satellite imagery from Heal the Bay Report Card was used to identify AB411 sites. These sites
were then assessed to determine if they were representative of the waterbody of interest. A visual
inspection from satellite imagery of the AB411 sample sites was performed to determine if the
sample site was on the enclosed side of the waterbody. In instances where the AB411 monitoring
site was found to be on the ocean side of the waterbody, these sample sites were labelled as not
representative.
After the AB411 analysis, it was determined that 10 of the 14 Tier 1 sites had representative data
which could be used for the first phase of the exceedance analysis (Table 2).
3 ftp://www.leginfo.ca.gov/pub/97-98/bill/asm/ab_0401-0450/ab_411_bill_19971008_chaptered.pdf 4 Heal the Bay Beach Report Card. http://brc.healthebay.org/
County Waterbody
Ventura Ventura Harbor
Ventura Channel Islands Harbor
Ventura Port Hueneme
Los Angeles Marina Del Rey
Los Angeles Redondo Beach Marina
Los Angeles Los Angeles Harbor
Los Angeles Los Alamitos Bay
Orange Anaheim Bay
Orange Huntington Harbor
Orange Bolsa Chica Bay
Orange Dana Point Harbor
San Diego Oceanside Harbor
San Diego Mission Bay
San Diego San Diego Bay
Page 4
EBE Reference Site Analysis
Table 2. Southern California Tier 1 Waterbodies with Representative AB411 Data.
County Waterbody
Ventura Ventura Harbor
Ventura Channel Islands Harbor
Los Angeles Marina Del Rey
Los Angeles Los Angeles Harbor
Los Angeles Los Alamitos Bay
Orange Huntington Harbor
Orange Bolsa Chica Bay
Orange Dana Point Harbor
San Diego Mission Bay
San Diego San Diego Bay
III. DATA COLLECTION
Enterococcus data were downloaded from the State Water Resources Control Board’s (SWRCB)
California Clean Beaches Program, which requires counties to conduct public health beach
monitoring of enterococcus, total coliform, and fecal coliform in order to comply with AB411.
The data was downloaded for the 10 waterbodies identified above for the time period 2010-2016
and filtered by county and date (Table 3).
Rainfall data was also needed in order to classify sampling periods as “wet” or “dry” and
determine wet and dry weather exceedances (discussed further in the Exceedance Analysis
section). Rainfall gauges (Table 3) were assessed for frequency of reporting (daily reporting
required), time period coverage (2010-2016), and proximity to the waterbody monitoring
locations (all gauges were within at least 10 miles of the sample site).
Page 5
EBE Reference Site Analysis
Table 3. Bacteria and Rainfall Data Sources.
Data Type
Source Website
Bacteria State Water Resources Control Board Beach Monitoring Data
http://www.swrcb.ca.gov/water_issues/programs/beaches/search_beach_mon.shtml
Rainfall National Oceanic Atmospheric Administration’s Precipitation Frequency Data Server
http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html?bkmrk=ca
Rainfall Ventura County Watersheds http://www.vcwatershed.net/hydrodata/
Rainfall Orange County Watersheds http://www.ocwatersheds.com/rainrecords/rainfalldata/stormdata/
Rainfall California Irrigation Management Information System (CIMIS)
http://www.cimis.water.ca.gov/
IV. EXCEEDANCE ANALYSIS METHOD
The exceedance analysis parameters (detailed below in Table 4) were based on the consensus
reached at the March 30th Stakeholder meeting5 and confirmed in a subsequent, summary email
on April 13th.
Table 4. Wet and Dry Enterococcus Analyses.
Weather Data Used Exceedance Threshold
Drya 2010-2016 Enterococcus data designated as dry Rolling geomeanb of 35 MPN/100 mL
Wetc 2010-2016 Enterococcus data designated as wet:
- Precipitation Day
Single sample maximum of 104 MPN/100 mL
- Day of precipitation+1 day after
- Day of precipitation+2 days after
- Day of precipitation+3 days after
a Dry weather was defined as a day that was not within 72 hours of a 1/10th of an inch of rainfall. b Rolling geomean includes a minimum of 5 samples within a 30 day period c Precipitation day was defined as a day that received at least 1/10th of an inch of rainfall. MPN = most probable number
Enterococcus data for each site were first compared to the rain gauge data to determine if a
sample was dry or one of the four wet classifications. Following this comparison, all dry data
were used to calculate rolling geomeans, which were compared against an exceedance threshold
of 35 most probable number (MPN)/100mL. Individual wet samples were compared against the
single sample maximum exceedance threshold of 104 MPN/100mL. To the extent practicable,
5 2017-03-30 Newport Bay Meeting Summary FINAL
Page 6
EBE Reference Site Analysis
the analysis followed the steps outlined in the Newport Bay Fecal Coliform TMDL 2016 Annual
Data Report.6
The following are a list of assumptions utilized for the analysis:
Units of most probable number (MPN) were considered equivalent to colony forming units
(CFU).
Non-detects were assigned a value of 3.7 Colony Forming Units MPN/100mL based on a
previous study by the City of Los Angeles Environmental Monitoring Division7 and
consistent with Newport Bay TMDL Annual Report.
In instances where there were multiple samples collected at the same station on a single dry
day, the samples were averaged for that given day. This averaged value was then used in
the geomean calculation.
In instances where there were multiple samples collected at the same location on a single
wet day, the samples were not averaged and instead were individually compared to the
single sample maximum threshold to determine exceedance.
Different enterococcus measurement methods (i.e., EPA 1600, membrane filtration, and
Enterolert) were assumed to be comparable (SWRCB guidance documents8).
Data qualifiers were treated as follows:
o Data labelled as “Duplicate” were discarded only in instances where there was another
data point collected at the same date and time (N=79).
o Data with the qualifier “P” for preliminary were excluded from the analysis (N=2).
o Data with the qualifier “C” for colony were excluded from the analysis (N=1).
o Data with the qualifier “E” for estimated were used in the analysis (N=107). This is
based on the guidance from the method EPA 1600 which states that when plate counts
fall outside the recommended range it is acceptable to assign an estimated a value.9
o Data labelled as > a certain value were set equal to the listed value.
Sample sites with limited dry weather data coverage (i.e., less than 10 geomeans; N= 4)
were excluded from analysis. Generally speaking, all dry weather sampling sites have at
least a year’s worth of data available.
None of the wet weather sites were excluded and all data were analyzed. Many more sites
had limited wet weather datasets (e.g., approximately 23 sample sites or 38% of all assessed
sites have less than 10 total wet weather sample points). Due to this and the infrequent
nature of rain events, we determined it was best to include all wet weather data in the
analysis. If it is decided that a similar cutoff should be used for both wet and dry data, the
6 County of Orange OC Public Works / OC Environmental Resources / Water Quality Compliance. 2016. Newport
Bay Fecal Coliform TMDL 2016 Annual Data Report. September 1, 2016. 7 Jurisdictional Groups, 2009. Reconsideration Elements for Bacteria TMDLs, July 2009. 25pp 8 SWRCB Functional Equivalent Document states “The RWQCBs shall aggregate data from all methods and
analyze as one data set.” (p. 71). 9 EPA, 2006. Method 1600: Enterococci in Water by Membrane Filtration Using membrane-Enterococcus Indoxyl-
β-D-Glucoside Aga (mEI). July 2006. Appendix B pp.2-3.
Page 7
EBE Reference Site Analysis
analysis can easily be updated to exclude sites with wet weather below a certain threshold
number of data points.
Table 5 provides a summary of the data analysis, which included approximately 10 distinct
waterbodies, 60 sample sites, 12,469 calculated geomeans, and 1,809 individual wet weather
samples across the four Southern California counties. Sites have been made anonymous to avoid
any bias in comparing sampling sites and waterbodies.
Table 5. Summary of Data Analyzed.
Waterbody County Sample Sites (dry) and (wet)
Dry Weather Geomeans
Wet Weather Single Samples
Waterbody A Ventura 1 76 9
Waterbody I Ventura 3 485 178
Waterbody D Los Angeles 1 915 159
Waterbody E Los Angeles 2 2,822 452
Waterbody F Los Angeles 6 1,199 256
Waterbody J Orange 1 61 9
Waterbody G Orange 12 2,007 287
Waterbody H Orange 13 2,275 354
Waterbody C San Diego 14 1,907 69
Waterbody B San Diego 6 (dry) 7 (wet) 722 36
Total 59 (dry) 60 (wet) 12,469 1,809
V. EXCEEDANCE ANALYSIS RESULTS
Dry Weather Exceedances
The results of the dry weather exceedance analysis for the 10 identified waterbodies are shown in
Figure 1. A total exceedance for each waterbody was calculated by summing the total geomean
exceedances and dividing by the total measured geomeans. Sites are organized from highest
(35%) to lowest (0%) percent exceedance. Two waterbodies had exceedances above 30% while
the other eight waterbodies were all less than 10%. As shown in Table 5, some waterbodies had
more sampling site coverage and, therefore, are likely to have better representation of the
waterbody as a whole. The waterbodies with both the highest and lowest percent exceedance are
only represented by a single sample site (Table 5).
Page 8
EBE Reference Site Analysis
Figure 1. Dry Weather Geomean Percent Exceedance by Waterbody.
The results of the exceedance analysis for dry weather per sample site are shown in Figure 2.
Sites are color coded to reflect the waterbodies they below to. Sites are organized from highest
to lowest exceedance percentage which ranged from 49% to 0% exceedance. The 15 sites on the
right side of the x-axis had no exceedances.
Data exceedance percentiles as well as the mean and median were calculated using the dry
weather sampling site data and are shown in Table 6. The 90th exceedance percentile is 19% and
the 75th percentile is 8%. Due to the long right tail of the data, the 25th and 10th percentiles are
both 0% exceedances and the mean is higher than the median (6.0% versus 2.4%).
0%
5%
10%
15%
20%
25%
30%
35%
Per
cen
tage
Ab
ove
Cri
teri
a (
%)
Dry Weather Samples 30-Day Rolling Geomeans - Percentage Above
Criteria (35 MPN/100 mL) per Waterbody
Page 9
EBE Reference Site Analysis
Figure 2. Dry Weather Rolling Geomean Percent Exceedance per Sample Site.
Page 10
Enclosed Bays and Estuaries Reference Site Analysis
Table 6. Dry Weather Exceedance Percentiles.
Percentile % Exceedance Number of sites
90th 17 6
75th 7.5 15
50th 2.4 30
25th 0 59
10th 0 59
Median 2.4 -
Mean 6.1 -
Wet Weather Exceedances
The results of the wet weather exceedance analysis for the 10 identified waterbodies are shown
in Figure 3. The stacked bar graphs distinguish wet weather exceedances that occurred on the
day of precipitation, as well as 1, 2, and 3 days after. The total wet weather exceedance for each
waterbody is given by the total height of the bar graph. Sampling did not always occur on each
of the four possible days of a specific rain event and, therefore, these results integrate data from
many individual wet weather sampling periods. There are sampling days for each of the four
possible wet weather days for all waterbodies with the exception of Waterbody J which lacks any
data on the 2nd day after a precipitation event. For the rest of the waterbodies, if an exceedance
for a certain day is not shown in the stacked bar graphs then the exceedance was 0%.
Some waterbodies had less sample coverage than others (Table 5). For instance, Waterbody J
(N=9) and Waterbody A (N=9) both had the least amount of wet weather data and therefore
these waterbodies have less data coverage than some of the others such as Waterbody E (N=
491) and Waterbody H (N =354). Waterbodies are organized from highest exceedance (53%) for
Waterbody F to the lowest (11%) for Waterbody B and Waterbody A.
The results of the exceedance analysis for wet weather monitoring per sample site are shown in
Figure 4. Sites are color coded to reflect the waterbodies they below to. The exceedance
percentage was calculated for total wet weather samples (precipitation day + 72 hours). Sites are
organized from highest (67%) to lowest exceedance percentage (0%). The 16 sites on the right
side of the x-axis had no exceedances.
Data exceedance percentiles as well as the mean and median were calculated using the wet
weather sample site data and are shown in Table 7. The 90th exceedance percentile was 51%
and the 75th percentile was 36%. Similar to the dry weather analysis, due to the long right tail of
the data the 25th and 10th percentiles are both 0% exceedance. The mean and median
exceedances were 21% and 18%, respectively.
Page 11
Enclosed Bays and Estuaries Reference Site Analysis
Figure 3. Wet Weather Exceedances Per Waterbody. The stacked bar graphs indicate exceedances that occur on the day of precipitation and subsequent three days following a precipitation event. *Waterbody J had no samples collected 2 days after a precipitation event.
0%
10%
20%
30%
40%
50%
60%
Per
cen
tage
Ab
ove
Cri
teri
a (
%)
Wet Weather Single Sample Maximum
Percentage Above Criteria (104 MPN/100ml) per Waterbody
Precipitation Day
1 Day after Precipitation
2 Days after Precipitation
3 Days after Precipitation
Page 12
Enclosed Bays and Estuaries Reference Site Analysis
Figure 4. Wet Weather (Precipitation + 72 hours) Percent Exceedance per Sample Site.
Page 13
Enclosed Bays and Estuaries Reference Site Analysis
Table 7. Total Wet Weather Exceedance Percentiles
Percentile % Exceedance Number of sites
90th 51 6
75th 36 15
50th 18 31
25th 0 61
10th 0 61
Median 18 -
Mean 21 -
Page 14
Enclosed Bays and Estuaries Reference Site Analysis
VI. SUPPLEMENTAL DATA AVAILABILITY AND ANALYSIS
In addition to the data collected from the SWRCB’s California Clean Beaches Program, a data
solicitation was also performed for individual county health and environmental departments as
well as other stakeholders who might have bacteria data pertaining to EBE waterbodies. Table 8
includes the full list of individuals who were contacted as part of the data solicitation as well as
weather or not data was received.
Table 8. Contact List for Supplemental EBE Bacteria Data
County Organization Individual Data Received
Ventura Ventura Countywide Stormwater Quality Management Program
Kelly Hahs N
Ventura County of Ventura Ewelina Mutkowska N
Ventura Ventura Environmental Health Department
Diane Wahl N
Ventura City of Ventura Joe Yahner N
Los Angeles County of LA Fred Gonzalez N
Los Angeles City of LA Rafael Valenzuela Y
Stacee Karnya
Los Angeles City of Redondo Beach Geraldine Trivedi Y
Los Angeles City of Long Beach Alvin Papa N
Los Angeles City of Redondo Beach, Geosyntec Stacy Luell Y
Christopher Wessel
Los Angeles City of LA, John L. Hunt Associates John Hunt N
Orange Sierra Club/OC Coastkeeper Ray Hiemstra N
Orange OC Public Works Amanda Carr Y
Rita Abellar
Jian Peng
San Diego City of SD Ruth Kolb, Andre Sonksen, Drew Kleis, Clem Brown
N
San Diego County of SD Jo Ann Weber, Todd Snyder
N
San Diego County Dept of Enviro Health (DEH) Ewan Moffat, Keith Kezer, Dominique Edwards
Y
San Diego City of Oceanside Justin Gamble Y
San Diego San Diego Unified Port District Stephanie Bauer N
San Diego Office of District Clerk Tim Duel Y
Cynthia Holder
The data solicitation resulted in additional data for one new waterbody and additional sample
sites for six waterbodies previously assessed with AB411 data. There were numerous cases
where the data solicitation resulted in data that was duplicative of that already received or data
that was not representative of the waterbody (e.g., on the ocean side of the EBE). We were
Page 15
Enclosed Bays and Estuaries Reference Site Analysis
unable to obtain any data for Port Hueneme (Ventura County) or Redondo Beach Marina (Los
Angeles County).
A summary of the supplemental data that could be used in a future analysis (e.g., is not
duplicative and is representative of the EBE) is presented in Table 9.
Table 9. Supplemental Data Solicitation.
County/Waterbody Data source Number of sites
Time Period Sampling Frequency and Type
Data sufficient to calculate dry geomeans and possible wet events
LA County / Marina Del Rey
TMDL Monitoring 9 2010-2016 5 samples/month both wet and dry
Orange County / Dana Point Harbor
Combination of programsa 14 2010-2016b 3-5 samples/month; mostly dry some wet
San Diego County / Mission Bay
County Dept. of Enviro. Health (DEH)
3 2013-2016 5 samples/month, both wet and dry
Data only sufficient to calculate possible wet events
LA County / Marina Del Rey
TMDL Monitoring 5 2010-2016 Monthly
LA County / Los Angeles Harbor
Terminal Island Water Rec. Plant NPDES Permit
1 2013, 2015, 2016
Monthly
San Diego County / Oceanside Harborc
Oceanside Harbor Sampling Program
3 2010-2016 Monthly
Orange County / Huntington Harbor
OC Public Works - Wetlands Monitoring
4 2010-2016 Intermittent; Some wet events
Orange County / Bolsa Chica Basin
OC Public Works - Wetlands Monitoring
1 2010-2016 Intermittent; Some wet events
a OC Public Works: SPEC Special Studies; DPHTMDL DPH Pathogen/Bacteria; SDR Unified Monitoring Program b Data coverage varies site by site. c Waterbody does not have any other AB411 data available.
The supplemental data varies by time period coverage, frequency of sampling, and wet and dry
sampling events. Three datasets were found to be sufficient to provide both dry weather
geomeans and wet weather analyses for Marina Del Rey, Dana Point Harbor, and Mission Bay.
Both Dana Point Harbor and Mission Bay have over 10 existing sample sites that were
assessed in the original exceedance analysis of AB411 data.
Marina Del Rey only has a single sampling site in the original exceedance analysis so
including the new supplemental data would significantly improve the data coverage of this
waterbody. In addition, the Marina Del Rey dataset comes from TMDL monitoring so its
sampling program is well suited for this exceedance analysis and would provide both wet
and dry datasets with minimal data processing required.
Page 16
Enclosed Bays and Estuaries Reference Site Analysis
Five of the datasets were sampled monthly or intermittently such that it would not be possible to
calculate dry weather geomeans, however, these datasets might provide additional data points for
wet weather events. The wet weather event coverage can only be determined by comparing the
sampling dates to nearby rain gauge data so until the rain gauge assessment is completed it is
unknown how many of the data points might be representative of wet weather. Four of these
datasets cover waterbodies which already have some data coverage while one monthly dataset,
for Oceanside Harbor, represents the only data available for this waterbody and therefore
including the data in an updated analysis would raise the list of total assessed waterbodies to 11.
Assessment of the additional data would require only a medium level of effort since most of the
data is already in a usable format and could be easily incorporated into the framework of the
existing analysis. Conducting the analysis of only the sites which have enough data for
geomeans would increase the total sampling sites assessed by 43% (raising the number from 60
to 86 total sites). This analysis will likely significantly change some of the individual waterbody
exceedance percentages (especially for Marina Del Rey), however it is likely that the general
trends displayed by the initial data will remain the same.
VII. SUMMARY
A summary of the exceedance analysis is provided below:
A total of 36 EBEs were identified in the four coastal Southern California counties.
o Only 14 of these sites were deemed to be suitable for use as a possible reference
site for Newport Bay.
Of the 14 sites, 10 had publicly available AB411 data representative of the
waterbody, which was collected from the SWRCB’s California Clean
Beaches Program.
Data from approximately 60 individual sites were compared to nearby rain
gauge data to determine wet and dry weather sampling events. These data
were then compared to wet and dry thresholds and exceedance percentages
were determined for each sample site and waterbody.
An additional data solicitation was conducted for all four counties resulting in three
datasets which could be used to calculate dry weather geomeans and wet weather
exceedances and five datasets which could be used to calculate wet weather exceedances
only. Some of these sites were only sampled monthly and therefore might provide wet
weather data but only if the monthly sampling happened to fall within 72 hours of a
precipitation event.
An analysis of the additional data would provide exceedance information for six already
assessed waterbodies, Marina Del Rey, Dana Point Harbor, Mission Bay, Los Angeles
Harbor, Huntington Harbor, Bolsa Chica Bay, and one previously unassessed waterbody,
Oceanside Harbor. Assessment of the additional data would require only a medium level
of effort, would increase the number of sites assessed by at least 43%, would provide
significantly improved analysis coverage for Marina Del Rey, and bring the number of
total assessed waterbodies from 10 to 11 via the assessment of Oceanside Harbor.
Staff WorkshopPART 3 OF THE WATER QUALITY CONTROL PLAN FOR INLAND
SURFACE WATERS, ENCLOSED BAYS, AND ESTUARIES OF CALIFORNIA—BACTERIA PROVISIONS AND A WATER QUALITY
STANDARDS VARIANCE POLICY
AND
AMENDMENT TO THE WATER QUALITY CONTROL PLAN FOR OCEAN WATERS OF CALIFORNIA—BACTERIA PROVISIONS
AND A WATER QUALITY STANDARDS VARIANCE POLICY
JULY 10, 2017
STEPHANIE ROSE, ENVIRONMENTAL SCIENTIST
Workshop Purpose
• To provide the public an opportunity to informally discuss the Bacteria Provisions and the Staff Report
• To assist the public with formulating written comments
• To assist staff in appreciating and addressing the public’s comments
2
History
Clean Water Act directs U.S. EPA to promulgate standards when it determines that a new or revised standard is needed and to adopt water quality standards to protect the public health and welfare.
• In 2012 U.S. EPA issued new recommended Recreational Water Criteria for Bacteria
• The 2012 Recreational Water Criteria for Bacteria are for use by states and tribes in adopting water quality standards
3
Current Status
• Most Regional Water Board basin plans are currently inconsistent with the 2012 Recommended Recreational Water Criteria for Bacteria
• The State Water Board staff developed the Draft Bacteria Provisions to provide efficient and consistent implementation statewide
• The Draft Bacteria Provisions and a Draft Staff Report including the Draft Substitute Environmental Documentation are now available for public comment (released June 30, 2017)
4
2012 Recommended Recreational Water Criteria for Bacteria
1. Based on two bacteria indicators:
• For Fresh Waters – E. coli and/or Enterococci
• For Marine Waters – Enterococci only
2. Based on one of two proposed illness rates
3. Consist of a geometric mean value and a statistical threshold value (STV) not to be exceeded more than 10% of the time
4. Define a duration and frequency of sampling and exceedance
5
2012 Recommended Recreational Water Criteria
6
Criteria
Elements
Estimated Illness Rate (NGI):
36 per 1,000 primary contact recreators
OR
Estimated Illness Rate (NGI):
32 per 1,000 primary contact recreators
Magnitude Magnitude
Indicator GM (cfu/100 mL) STV (cfu/100 mL) GM (cfu/100 mL) STV (cfu/100 mL)
Enterococci
(marine and fresh) 35 130 30 110
OR
E. coli – (fresh)126 410 100 320
NGI = NEEAR – GI illness, NEEAR = National Epidemiological and Environmental Assessment of Recreational Water
GM = geometric mean
STV = statistical threshold value cfu = colony forming units
mL = milliliters
Elements of the Bacteria Provisions
• Beneficial Use
• Provides a limited water contact recreation (LREC-1) beneficial use definition.
• Water Quality Objectives
• Applicable to waters with water contact recreation (REC-1) uses
• Defines the applicable bacteria indicator, e.g. E. coli, Enterococci
• Defines an illness rate
• Defines an averaging period to determine compliance
• Implementation Provisions
• Methods for addressing natural sources of bacteria within context of a TMDL
• Method for suspension of the REC-1 use during high flows
• Method for suspension of the REC-1 use during a specific season
• Water Quality Standards Variance
7
Beneficial Use
Limited REC-1
• A beneficial use that recognizes that body contact is limited in the waterbody due to physical conditions, such as restricted access and very low water depths
• Proposed definition:
• Limited Water Contact Recreation (LREC-1): Uses of water that support limited recreational activities involving body contact with water, where the activities are predominantly limited by physical conditions such as very shallow water depth or restricted access and, as a result, body contact with water and ingestion of water is infrequent or insignificant.
8
Elements of the Water Quality Objective
Fresh Water Bacteria Indicator (where the salinity is less than 10 ppth 95 percent or more of the time)
• Proposing the use of E. coli• E. Coli is a better indicator than total and/or fecal coliform
• Enterococci can give false positives in fresh waters
Estuarine Water Bacteria Indicator (where the salinity is equal to or greater than 10 ppth 95 percent or more of the time)
• Proposing the use of Enterococci
• Only indicator recommended for saline waters
9
Elements of the Water Quality Objective
Marine Water Bacteria Indicator
• Proposing the use of Enterococci
• Only indicator recommended for marine waters
• Proposing to eliminate objectives for total and fecal coliform in the Ocean Plan
• Monitoring and beach notifications will still be required by AB 411 (Title 17 section 7958)
10
Elements of the Water Quality Objective
Illness Rate
• The expression of the illness rate has changed
• The 1986 illness rate included only gastrointestinal illnesses with fever
• The 2012 illness rate included gastrointestinal illnesses with or without fever
• The 2012 Recommended Recreational Water Criteria for Bacteria contains two illnesses rates that are both protective of public health
• Proposing the use of U.S. EPA’s estimated illness rate of 32 per 1,000 recreators for fresh, estuarine and marine waters
• This is the slightly more conservative illness rate of the two recommended by U.S. EPA.
• As Lake Tahoe is a Outstanding Natural Resource Water we are proposing a illness rate that is comparable to its current illness rate.
11
Proposed REC-1 Bacteria Water Quality Objectives
12
Applicable Waters
Objective
Elements
Estimated Illness Rate (NGI):
32 per 1,000 water contact recreators
Magnitude
Indicator GM (cfu/100 mL) STV (cfu/100 mL)
All waters, except Lake Tahoe,
where the salinity is less than 10 ppth
95 percent or more of the time
E. coli 100 320
Lake Tahoe E. coli 17 55
All waters, where the salinity
is equal to or greater than 10 ppth
95 percent or more of the time
Enterococci 30 110
The waterbody GM shall not be greater than the applicable GM magnitude in any six-week interval, calculated
weekly. The applicable STV shall not be exceeded more than 10 percent of the time, calculated monthly.
NGI = National Epidemiological and
Environmental Assessment of
Recreational Water gastrointestinal
illness rate
GM = geometric mean
STV = statistical threshold value
cfu = colony forming units
mL= milliliters
ppth = parts per
thousand
Elements of the Water Quality Objective
Averaging Period to Determine Compliance
• The geometric mean duration is proposed as a 6-week rolling geometric mean, calculated weekly
• This allows for a significantly sufficient number of samples for calculating attainment of the water quality standard, while allowing for a quick reporting response
• The statistical threshold value (STV) is proposed to not be exceed more than 10 percent of the time, calculated monthly
13
Implementation Provisions – Natural Sources
• Proposing two approaches for addressing natural sources of bacteria levels within the context of a TMDL
• Reference System/Antidegradation Approach
• Bacteria water quality is at least as good as that of a natural (reference) system
• No degradation of existing water quality is allowed, where it is better than the natural system (antidegradation)
• Only allows adjustment of the STV
• Natural Source Exclusion Approach
• Requires the control of all anthropogenic sources of bacteria
• Requires the identification and quantification of natural sources of bacteria
• Exceedance are allowed based on residual exceedances of natural sources
• Only allows adjustment of the STV
14
Implementation Provisions – Natural Sources
• Allows the Regional Water Boards to use these approaches without having to adopt them into their individual basin plans
• Allows resources for remediation to be directed toward anthropogenic sources instead of areas with natural sources of bacteria
• Prevents the over-treatment of natural sources of bacteria
15
Implementation Provisions – High Flow Suspension
• High Flow Suspension of REC-1 Uses
• When water conditions are considered unsafe for REC-1 uses due to high water flow or velocity
• A use attainability analysis and U.S. EPA approval is required
16
Implementation Provisions – Seasonal Suspension
• Seasonal Suspension of REC-1 Uses
• When water conditions are considered inapplicable or unsafe for the REC-1 beneficial use due to low water flows, low water temperatures, or conditions that freeze waters
• A use attainability analysis and U.S. EPA approval is required
17
• Identify the method for using of a water quality standards variance
• “A time-limited designated use and criterion for a specific pollutant(s) or water quality parameter(s) that reflect the highest attainable conditions during the term of the water quality standard variance.”
• Defined in 40 Code of Federal Regulations section 131.14
• This regulation includes applicability, requirements for submission and how water quality standards variances are implemented with NPDES permits
• U.S. EPA approval is required.
18
Water Quality Standards Variance
Schedule
• August 1, 2017 – State Water Board Hearing
• To hear oral comments
• No formal action
• August 16, 2017 – Public Comment Deadline
• August – November 2017 – Response to Comments
• December 5, 2017 – State Water consideration
19
Any Questions?
20
Staff Contacts
• Program Manager - Nick Martorano – (916) 341-5290
• Staff Contact – Fresh Waters – Stephanie Rose – (916) 341-5574
• Staff Contact – Ocean Waters – Michael Gjerde – (916) 341-5283
• Website - http://www.waterboards.ca.gov/bacterialobjectives/
21
