20 YEAR REPORT for

Report prepared by: Pam Krone (CMSF), Lisa Emanuelson (CMSF) and Bridget Hoover (MBNMS) MBNMS Snapshot Day organized by:

Monterey Bay Sanctuary Citizen Watershed Monitoring Network Supporting citizen monitoring programs throughout the Monterey Bay National Marine Sanctuary. (831) 647 -4227 www.montereybay.noaa.gov

Coastal Watershed Council A public education non-profit advocating the preservation and protection of coastal watersheds through the establishment of community-based stewardship programs. (831) 464 -9200 www.coastal- watershed.org

Monterey Bay National Marine Sanctuary (MBNMS) Water Quality Protection Program Promoting clean water in the watersheds along nearly 300 miles of the Sanctuary’s coastline. (831) 647 -4217 www.montereybay.noaa.gov

With assistance from:

San Mateo County Resource Conservation District Helping people help the land since 1939. (650) 712-7765 www.sanmateorcd.org

Watsonville Wetlands Watch Advocating for wetlands, teaching school students, restoring habitats and preserving what remains. (831) 728-1156 www.watsonvillewetlandwatch.org

Upper Salinas-Las Tablas RCD Provide services and education to landowners supporting their management and stewardship of soil, water and natural resources. (805) 434-0396 www.us-ltrcd.org Executive Summary Snapshot Day began as a volunteer monitoring effort on April 22, 2000, the first official Earth Day, through a joint collaboration with the Coastal Watershed Council (CWC), The Ocean Conservancy and Monterey Bay National Marine Sanctuary (MBNMS). Snapshot Day was intended to provide a “snapshot” of the quality of water flowing into MBNMS while raising awareness about watershed health. Snapshot Day (SSD) has become an annual event that has created partnerships, drawn over 3,395 volunteers to date, and has helped foster an ethic of watershed stewardship for local citizens. The twenty years of data collected by volunteers has become a valuable source of water quality data for the region.

Since 2000, volunteers have sampled as many as 261 sites on the central coast of California. They measure pH, dissolved oxygen, conductivity, turbidity, water clarity, and water temperature. They collect water samples for lab analysis of nitrate, orthophosphate, total coliform, and Escherichia coli (E. coli). For purposes of this 20 year report, only sites monitored at least five years are included in the analysis. There were 192 sites monitored at least five years (Fig ES1). Data was analyzed to determine how often sites exceeded water quality objectives (WQOs), whether conditions were improving or getting worse, and how representative the data is compared to the Central Coast Ambient Monitoring Program (CCAMP).

Results reveal that seven sites never exceeded any WQOs. They include Whitehouse Creek (202-WHITE-11), San Vicente Creek in Davenport (304-SANVI-21), Big Creek at Hwy 1 (308- BIGCR-31), Dani Creek at Hwy 1 (308-DANIC-31), Zayante Creek at Laurel Square (304-ZAYAN- 21), Mill Creek at Hwy 1 (308-MILLC-31) and Prewitt Creek at Hwy 1 (308-PREWI-31). Eleven sites exceeded all laboratory WQOs more than 50% of the time. These sites were located in Elkhorn Slough, Upper Moro Cojo Slough and 9 sites in the Lower Salinas River watershed. Waterbodies were identified as Areas of Concern when one or more sites on that waterbody exceed the WQOs for three or more analytes (field and lab). Over 20 years, there were 59 waterbodies that were never listed as an Area of Concern. There were 9 waterbodies listed as Areas of Concern for more than 10 years.

Nitrate, orthophosphate and E. coli were evaluated for trends using the Mann-Kendall test and the calculation of an Arkitas-Sen-Theil slope. Sites had to be monitored at least 5 years and have at least one WQO exceedance to be included in the analysis. Eleven sites demonstrated trends for nitrate: 5 improving and 6 worsening. Nine sites demonstrated trends for orthophosphate: 5 improving and 4 worsening. Twenty sites demonstrated trends for E.coli: 14 improving and 6 worsening.

Snapshot Day would not be possible without an army of volunteers collecting water samples at over 100 sampling sites spread out over 300 miles within a matter of hours. When results were compared with CCAMP, a Central Coast Water Quality Control Board program, the rating comparison between the 37 overlapping CCAMP and Snapshot Day sites for nitrate, orthophosphate and E. coli showed a good level of coincidence between the two programs despite the difference in sampling regimes and years sampled.

Figure ES1. Map of Snapshot Day monitoring sites, years monitored, and total number of water quality exceedances for all parameters measured.

Snapshot Day 20 Year Report

MONTEREY BAY NATIONAL MARINE SANCTUARY

SNAPSHOT DAY TWENTY YEAR REPORT 2000-2019

1. INTRODUCTION

The Citizen Watershed Monitoring Network (Network) was formed as a consortium focused on organizing citizen monitoring programs to provide a cost effective way to build an informed community with knowledge about watersheds, pollution prevention, threats to good water quality and to train volunteers to collect robust and meaningful water quality data. On that first Snapshot Day in 2000, 110 trained citizen science volunteers collected water samples in four counties at 122 sites on 89 waterways in 10 watersheds along a 279-mile stretch of the California central coast. Water from each of these watersheds flows into MBNMS, the third-largest of 14 federally designated underwater areas protected by NOAA’s Office of National Marine Sanctuaries. Citizen science volunteers included retirees interested in learning more about ocean health, college students wanting hands on experience in the sciences, citizens wanting to make a difference in their community and sanctuary staff and partners hoping to create a successful and enduring volunteer monitoring program. The Network includes groups that monitor the health of the ten watersheds that flow into MBNMS. The Coastal Watershed Council and California Coastal Commission, along with MBNMS, formed the core of the Network and continue to work together on projects with volunteers including Snapshot Day, First Flush and Urban Watch monitoring programs.

MBNMS encompasses more than 4,600 square nautical miles of ocean and includes many diverse ecosystems encompassing over 500 different species of fish, 180 species of shorebirds and seabirds, and 34 species of marine mammals. Ten major watersheds drain over 7000 square miles of land to the coastal zone of the sanctuary. Land uses in these watersheds include urban and suburban development, intensive agricultural uses, and rural lands. Waters flowing through these watersheds transport pollutants such as sediments, nutrients, pesticides, oils, and pathogens, through the rivers, wetlands, harbors and coastal zone of the sanctuary where they can affect coastal ecosystems, fishes and other resident aquatic organisms.

Water quality monitoring allows resource managers to understand the general health of the sanctuary and its watersheds, identify water quality problems, determine water quality trends over time, and inform water quality policy. Citizens involved in the monitoring effort have an opportunity to contribute to the regional understanding of water quality and to discover how the way we live on land influences pollutants entering streams, estuaries and ultimately the sanctuary.

Since its inaugural year in 2000, Snapshot Day continues on the first Saturday of every May as an annual citizen science monitoring effort for which volunteers have sampled as many as 261 sites on the central coast of California in an effort to understand the quality of water flowing into the sanctuary. Each year hundreds of volunteers sample sites along the central coast, contributing to an extensive data set of water quality information. Water quality measurements include pH, dissolved oxygen, conductivity, turbidity, water clarity, water temperature, nitrate, orthophosphate, total coliform, and Escherichia coli (E. coli). Knowing the concentrations of these contaminants informs decision making

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Snapshot Day 20 Year Report and allows agencies to improve management of our natural resources.

A natural outcome of Snapshot Day is a community of people committed to environmental stewardship and conservation. By involving citizens in collecting water samples, Snapshot Day provides education about watersheds and the important role they play in ocean health. Snapshot Day could not be conducted across such a broad geographical region on a single day without the help of volunteers. In 2000, 110 volunteers monitored 122 sites from coastal San Mateo County to San Luis Obispo County. In 2003, Snapshot Day was implemented along the entire coast of California when 637 volunteers monitored 546 sites. In 2009, for the special 10 year anniversary event, our largest central coast turnout of 224 volunteers helped to monitor 180 sites. Over the past twenty years, from 2000-2019, the 3,395 Snapshot Day citizen science volunteers have donated more than 17,000 hours, which is equivalent to $361,000 of in-kind donations. Many Snapshot Day volunteers return each year; some have been involved in this sampling effort for all twenty years and often request to monitor the same sites year after year in the community where they live, contributing to a sense of ownership and directly observing changes over time.

In this 20th anniversary report, we present the results of three statistical analyses of Snapshot Day data collected from 2000-2019: 1) characterization of the deviation of analyte concentrations from water quality objectives (exceedances), 2) assessment of trends over time of three water quality constituents, and 3) representativeness of Snapshot Day data via comparison to the more frequent sampling effort conducted by the Central Coast Ambient Monitoring Program (CCAMP) at overlapping sites. Additionally, we review the importance of citizen science efforts in collecting water quality data across a broad geography and at a larger number of sites than could be monitored without the contribution of volunteers. A sampling effort of this scope using professional field technicians would be cost prohibitive.

Regulatory Background MBNMS was designated on September 18, 1992, and is administered by the National Oceanic Atmospheric Association (NOAA). It was established for the primary purpose of resource protection, as well as research, education, and public use of this national treasure. MBNMS extends from the mean high water mark to as far as 53 miles offshore, covering everything below the water’s surface from Marin County to Cambria. To implement the mandates of the National Marine Sanctuaries Act, the regulations for MBNMS (15 CFR 922.132) generally prohibit discharges within the boundaries of the sanctuary with limited exceptions for dredged material, and fishing and vessel operation. Discharges beyond the boundary of the sanctuary that subsequently enter and injure sanctuary resources or qualities are similarly prohibited.

On March 15, 2012, the Central Coast Regional Water Quality Board (CCRWQB) adopted a Conditional Waiver of Waste Discharge Requirements (Agricultural Order No. R3-2012-0011). The CCRWQB regulates discharges from irrigated agricultural lands to protect surface water and groundwater, under a Conditional Waiver of Waste Discharge Requirements that applies to owners and operators of irrigated land used for commercial crop production. The CCRWQB is focusing on priority water quality issues, such as pesticides and toxicity, nutrients, and sediments – especially nitrate impacts to drinking water sources. More information can be found at http://www.waterboards.ca.gov/centralcoast/water_issues/programs/ag_waivers/index.shtml

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Snapshot Day 20 Year Report

The CCRWQB also oversees a Storm Water Program to prevent storm water runoff from acting as the vehicle for the discharge of pollutants to surface water bodies. The Storm Water Program is a National Pollutant Discharge Elimination System (NPDES) Program implemented in two phases (Phase I and Phase II). The November 16, 1990 Federal Register describes the requirements of the Phase I Regulations and the December 8, 1999 Federal Register describes the Phase II regulations. The State of California carries out the Storm Water Regulations according to the California Water Code. The City of Salinas holds the only individual Phase I municipal storm water permit in the Central Coast Region. On March 10, 2003, Operators of Phase II Regulated Small Municipal Separate Storm Sewer Systems (MS4s) were required to obtain permit coverage. On February 5, 2013, the proposed final draft of the Phase II Small MS4 General Permit was adopted and became effective on July 1, 2013 (Order No. 2013- 0001). More information can be found at: http://www.waterboards.ca.gov/water_issues/programs/stormwater/municipal.shtml

With both the implementation of the Agricultural Order and the MS4 Storm Water permits, there is much more regulatory oversight and requirements to reduce pollutants loads from these sources into surface waters of the state.

2. METHODS

2.1. VOLUNTEERS

Volunteers are truly the lifeblood of citizen science programs such as Snapshot Day. The Network recruits an average of 170 volunteers a year for the Snapshot Day citizen watershed monitoring program (Table 1). Volunteers are recruited through many avenues: advertisements in local newspapers; professors and teachers at local colleges, universities and high schools; emails to partner agencies, email list serves, former volunteers, volunteers from other MBNMS programs; and flyers at colleges, universities, and community bulletin boards. Many volunteers learn about Snapshot Day through a presentation by a Snapshot Day coordinator in their classroom or club. Through this outreach, people residing in sanctuary watersheds are introduced to MBNMS as a geographic and governmental entity, learn about the purpose of monitoring programs related to ocean health, and are offered an opportunity to contribute to a broader water quality monitoring effort than would be possible on this scale in the absence of a volunteer network.

Volunteer training sessions are conducted in the four regions where Snapshot Day samples are collected: coastal San Mateo County, Santa Cruz County, Monterey County and San Luis Obispo County. CWC staff train and coordinate volunteers in Santa Cruz County while MBNMS staff train and coordinate volunteers in San Mateo, Monterey and San Luis Obispo counties. During training, volunteers are provided an overview of the purpose for monitoring and information on National Marine Sanctuaries. Training also includes instructions and demonstrations on how to collect samples for lab analysis of E. coli, nitrate and phosphate as well as how to collect field measurements for temperature, conductivity, pH and water clarity/turbidity using provided equipment. Training includes familiarizing volunteers with standardized monitoring protocols such as wearing gloves to avoid sample contamination while protecting hands from pollutants, triple rinsing sample bottles and triple rinsing

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Snapshot Day 20 Year Report field equipment. Volunteers are shown how to complete datasheets, given guidance on field safety and provided examples of some basic “do’s” and “don’ts”. Each set of equipment includes a detailed map with directions to sites, in-the-field insturctions, data sheets, disposable gloves, deionized rinse water, digital thermometer, pH strips, Oakton conductivity meter, transparency tube or turbidity meter and laboratory sample collection bottles.

Four hubs, located in each Snapshot Day region, serve as the meeting spots for volunteers prior to and after heading out to assigned sites. Once the teams of volunteers have visited all assigned sites, iced samples and equipment are delivered back to the hub in the shortest time possible. Samples are then taken to a local certified laboratory for analysis; in a few instances samples travel over 100 miles to get to a laboratory.

2.2. SITE SELECTION

Sites were chosen based on existing sites monitored by the Central Coast Ambient Monitoring Program (CCAMP), sites monitored by other programs, and sites with public access in streams up and down the coast to ensure geographic representation. The monitoring effort was designed to measure basic water quality parameters that are indicators of stream ecosystem health within important waterbodies draining into MBNMS. Not all sites were measured each year due to programmatic changes, funding constraints, or lack of flowing water. Water quality measurements were collected at a total of 261 different sites (annual range of 110 - 192 sites) along the central coast every spring between 2000-2019 (Fig. 1).

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Snapshot Day 20 Year Report

2.3. STATISTICS - EXCEEDANCES

Snapshot Day Water Quality Objectives (WQOs) were adopted from objectives developed by the U.S. Environmental Protection Agency (USEPA), the Central Coast Regional Water Quality Control Board (CCRWQCB) Basin Plan and the Central Coast Ambient Monitoring Program (CCAMP) as guidelines by which to determine impairment of a water body (Table 2; CCRWQCB 2011, USEPA 2012). These objectives in Table 2 are used except in cases where the CCWQRB adopted Basin Plan Amendments as a result of a Total Maximum Daily Load (Table 3).

Table 2. Water Quality Objectives for Snapshot Day water chemistry and their source.

Analyte Water Quality Objective Objective Source

Dissolved Oxygen Not < 7 or > 13 California Basin Plan Objective

EPA Ambient Water Quality E. coli (MPN/100 mL) Not to exceed 2351 Criteria

Central Coast Ambient Nitrate as N (mg/L) Not to exceed 1.03 Monitoring Program (CCAMP)

Central Coast Ambient Nitrate as N (mg/L) Not to exceed 1.03 Monitoring Program (CCAMP)

Central Coast Ambient Orthophosphate as P (mg/L) Not to exceed 0.122 Monitoring Program (CCAMP)

pH Not < 6.5 or > 8.5 General Basin Plan Objective

Central Coast Ambient Turbidity (NTU) Not to exceed 251 Monitoring Program (CCAMP)

Central Coast Ambient Water Temperature (⁰C) Not to exceed 214 Monitoring Program (CCAMP)

1 Environmental Protection Agency, Updated WQO. 2 Central Coast Ambient Monitoring Program, Pajaro River Watershed Characterization Report 1998, rev 2003. 3 Williamson, The Establishment of Nutrient Objectives, Sources, Impacts and Best Management Practices for the Pajaro River and Llagas Creek, 1994. 4 Moyle, P. 1976. Inland Fisheries of California. University of California Press.5 Sigler, J.W., T.C. Bjornn and F.R. Everest. 1984. Effects of chronic turbidity on density and growth of steelhead and coho salmon. Transactions of the American Fisheries Society 113: 142-150

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Snapshot Day 20 Year Report

Table 3. Basin Plan Amendments by the CCRWQCB for specific waterbody TMDLs. Snapshot Day is a dry season event.

Dry Season Water Quality Analyte Waterbody Objective (mg/L)

Total Nitrogen as N Moro Cojo Slough 1.7

Salinas River downstream of Nitrate as N 1.4 Spreckels

Llagas Creek, Carnedero Creek, Nitrate as N 1.8 Uvas Creek

Alisal Creek, Natividad Creek, Nitrate as N 2 Gabilan Creek

Nitrate as N Old Salinas River 3.1

Merrit Ditch, Reclamation Canal, Alisal Slough, Santa Rita Creek, Nitrate as N 6.4 Espinosa Slough, Tembladero Slough, Blanco Drain

Salinas River upstream of Nitrate as N Spreckels, Chualar Creek, Quail 10 Creek, Esperanza Creek

Salinas River downstream of Spreckels, Gabilan Creek, Orthophosphate as P 0.07 Natividad Creek, Alisal Creek, Old Salinas River

Merrit Ditch, Reclamation Canal, Alisal Slough, Santa Rita Creek, Orthophosphate as P Espinosa Slough, Tembladero 0.13 Slough, Blanco Drain, Moro Cojo Slough

An exceedance occurred when the concentration or measure of a given analyte was above (or below, where applicable) the WQO. Dissolved oxygen and pH have both upper and lower water quality objectives, in which case exceedance occurs when either limit is surpassed. For sites monitored for five or more years, we identified the number of years sampled, the number of years the WQO was exceeded, and the percent of years the WQO was exceeded for each analyte.

In order to evaluate and compare different regions within the central coast, we consolidated sites into hydrologic units (HU) and assessed the number of sites in each HU that exceeded the WQO (Figures 4- 7). This allowed us to compare the performance between regions for all analytes in terms of the percent of years the WQO was exceeded for sites in that HU.

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Snapshot Day 20 Year Report

In the annual Snapshot Day reports, we determine which sites exceeded the WQOs for three or more analytes (field and lab) and associated them with waterbodies that we designated as Areas of Concern. A waterbody that is listed as an Area of Concern for a particular year has at least one site that exceeded three WQOs that year. Note that in early annual Snapshot Day Annual reports, WQOs were based on different standards that have been updated over the last 20 years. The result is that the number of Areas of Concern identified in those early reports may vary from the number reported here.

2.4. STATISTICS - TRENDS

Trends were calculated for a selection of three analytes: nitrate, orthophosphate, and E. coli. Trend testing was performed on sites with at least 5 years of measurements for each analyte where the concentration exceeded the WQO for at least one sampling event. In instances where a site was sampled for five or more years, but one analyte was measured only four of those years, the trend assessment was not conducted for that particular analyte, though it was conducted for the other two.

Trends were evaluated using the monotonic, non-parametric Mann-Kendall test (Kendall 1928, Mann 1945, Kendall 1948). This test was chosen because it does not require that the data conform to any particular distribution. This is important for maintaining comparability of data in a large data set such as Snapshot Day since water quality data are typically positively skewed and often to varying degrees, so conducting transformations in order to perform parametric statistics is less accurate. The CCRWQB also uses the Mann-Kendall trend test, therefore a comparison of CCAMP statistical results with those from Snapshot Day at overlapping sites may highlight some of the similarities and differences between the two monitoring programs. The Mann-Kendall test also presumes that the data are independent temporally, which is the case in the Snapshot Day time series given the annual separation between samples. Mann-Kendall additionally requires that seasonality is removed from the data, and as Snapshot Day samples are taken once every spring, seasonality is not a factor in these data. Because the Mann-Kendall test is monotonic, we used the Sen-Theil slope to estimate the magnitude of the trend. Additionally we calculated the 95% Confidence Interval (CI) for this slope to graphically represent the range of most likely trends. If both the upper and lower CIs are positive, then this lends further credence to a positive trend. Similarly if both are negative this signifies a likely downward trend. However if one CI is positive and the other negative, then the results of the trend test are considered uncertain. In this case we consider a trend to most likely have occurred, but with some room for doubt.

The null hypothesis of the Mann-Kendall test is that no trend exists (Helsel & Hirsch 2002). We set two different levels of significance showing both a p-value of 0.05 and 0.10, so that we could identify sites where there is a the 95% or 90% confidence level that a trend exists. With the two different p-values, readers can evaluate for themselves what level of confidence to choose. Given the small sample size of Snapshot Day data, we felt readers might be interested in both results in order to evaluate for themselves the odds and preferences for making a Type I versus Type II error. R statistical software and the NADA package was used for the Mann-Kendall test on measurements of the three analytes (R Core Team 2013, Lee 2013). The NADA package for R was used to evaluate censored data (non-

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Snapshot Day 20 Year Report detects) for the trend test and to graphically portray censored values as hashed lines between zero and the detection limit for that observation. This package generated the number of samples (n) used in the analysis, Kendall’s tau (τ), p-value, and Sen-Theil slope, which was reported along with graphs of the sites where a significant trend could be detected. Upper and Lower 95% Confidence Intervals (CI) for the Sen-Theil trends were developed using the Openair Package (Carslaw & Ropkins 2014).

2.5. COMPARISON OF CCAMP AND SNAPSHOT DAY RATING AND TRENDS

CCAMP and Snapshot Day programs adopted some sites that share the same sampling location, designated as “overlapping sites.” Both programs have engaged in extensive monitoring of these sites, although over different time frames and at different intervals. CCAMP has two types of sites, coastal confluence and watershed, with different monitoring regimes. CCAMP has conducted monthly water quality monitoring at coastal confluence sites on the central coast of California since 2001. Additionally, CCAMP rotates through an additional 30 watershed sites annually in five watershed areas since 1999. Snapshot Day monitoring takes place once a year in May; however not all sites are monitored each year. A total of 13 coastal confluence and 24 watershed sites overlap with Snapshot Day sites monitored for 5 or more years, based on a proximity of 200 meters from geo-referenced site data (Fig. 1).

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Snapshot Day 20 Year Report

Figure 1. Twenty years of unique Snapshot day sites in red and overlapping sites monitored by CCAMP.

CCAMP rates sites for each analyte using the following designations: excellent, good, fair, impacted, or severely impacted. This rating is based on a score card approach used prior to October 2014 involving examination of water quality parameters against multiple thresholds appropriate to determining

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Snapshot Day 20 Year Report aquatic health (CCRWQCB 2014). All analytes and in-situ measurements taken on Snapshot Day are also measured by CCAMP, and comparisons were made for nitrate, orthophosphate and E. coli. We did not use a rating system for Snapshot Day results, however we show the percent of years the WQO was exceeded at overlapping sites. This percent can be compared with the CCAMP rating to assess comparability between the results of the two programs.

In addition, we compared the results of our statistical trend test in terms of whether a trend was found and whether there was a trend identified by the CCAMP program at overlapping sites. Similarities and differences exist between the CCAMP trend analysis and that conducted for Snapshot Day in terms of numbers of samples, span of years, and frequency of monitoring. Both CCAMP trends and Snapshot Day trends were assessed using the same statistical software (R and the NADA package) and both involved a Mann-Kendall trend test(personal communication Dave Paradies 2014). In addition to a trend analysis, CCAMP also shows the results of a change point analysis. CCAMP had a larger sample set (n = 24-190) compared with Snapshot Day (n = 5-20) data. CCAMP assigned a p-value of 0.05 for significance in their trend evaluation as did the Network-for this comparison with Snapshot Day. The date range for CCAMP trend analysis at coastal confluence sites was from 2001-2015 and for CCAMP watershed sites which varied due to the rotational schedule, but normally included 2-3 years of data. The date range for Snapshot Day data varied by site, with years ranging between 2000-2019 with 5 to 20 years of data. CCAMP trend analysis results are available on their website at http://www.ccamp.info.

2.6. QUALITY ASSURANCE AND DATA CENSORING

The protocols for sample handling, analytical methods, equipment calibration and data management are described in the California Coast Wide Snapshot Day 2003 Quality Assurance Project Plan (QAPP), approved by the State Water Resources Control Board in 2003. The approved QAPP outlines standard operating procedures for field measures and lab analysis including percentages of duplicate samples, field blanks, split samples, known laboratory controls, replicate measurements to assure accuracy, precision, completeness and representativeness of samples and data collected. In the initial years, Snapshot Day samples were sent to eight different labs for analysis. In more recent years, samples were sent to only four different ELAP certified labs: Monterey Bay Analytical Services, County of San Mateo Public Health Laboratory, City of Watsonville, and County of San Luis Obispo Public Health Laboratory.

3. RESULTS

Snapshot Day is a single day volunteer monitoring event that occurs annually in the spring of the year on the first Saturday of May. There were a total of 261 Snapshot Day sites that were monitored at least one year and a total of 192 sites that were monitored for 5 or more years (Fig. 2).

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Snapshot Day 20 Year Report

3.1. STATISTICS - EXCEEDANCES

Snapshot Day sites are located in urban, agriculturally dominated and open space landscapes. Of the sites monitored for 5 or more years, only 7 sites (4%) never exceeded any of the Water Quality Objectives (WQO). These were Whitehouse Creek east (202-WHITE-11) , San Vicente Creek in Davenport (304-SANVI-21), Big Creek at Hwy 1 (308-BIGCR-31), Dani Creek at Hwy 1 (308-DANIC-31), Zayante Creek at Laurel Square (304-ZAYAN-21), Mill Creek at Hwy 1 (308-MILLC-31) and Prewitt Creek at Hwy 1 (308-PREWI-31). Many of these sites are in coastal areas with minimal human development or are located in a watershed upstream from more densely developed areas (Fig. 2a-2c). Of the sites monitored for 5 or more years, there were no sites that exceeded the WQOs for all analytes all years monitored; however 11 sites exceeded all lab WQOs more than 50% of the years monitored. Elkhorn Slough at Garin Road (306-ELKHO-34), Upper Moro Cojo Slough (306-MOROC-31), Upper Alisal Creek at North Madeira (309-ALISA-32), Gabilan Creek at Independence Road (309-GABIL-31), Natividad Creek at Las Casitas Road (309-NATIV-31), the Reclamation Ditch at Davis Road (309-RECDI-31), Santa Rita Creek at two sites (309-SRITA-34 and 309-SRITA-35), Tembladero Slough at two sites (309-TEMBL-31 and 309-TEMBL-33), and Upper Natividad Creek at E. Boronda (309-UPPER-31) all exceeded nitrate, orthophosphate and E. coli standards for more than half the years monitored. Four sites Harkins Slough at Harkin Valley Road (305-HARKI-21), Harkins Slough at Pajaro Valley Water Management District (305-HARKI-22), Elkhorn Slough at Hudson’s Landing (306-ELKHO-32), and Upper Moro Cojo Slough (306-MOROC-31) exceeded at least two of the in situ field measured WQOs more than half the years monitored. Sites with frequent lab or field measured exceedances are in agricultural dominated landscapes or near urbanized centers.

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Snapshot Day 20 Year Report

Figure 2a. Northern Snapshot Day sites showing number of years monitored and number of exceedances. Hydrologic Unit Codes (HUCs) are represented by color and number.

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Snapshot Day 20 Year Report

Figure 2b. Central Snapshot Day sites showing number of years monitored and number of exceedances. Hydrologic Unit Codes (HUCs) are represented by color and number.

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Snapshot Day 20 Year Report

Figure 2c. Southern Snapshot Day sites showing number of years monitored and number of exceedances. Hydrologic Unit Codes (HUCs) are represented by color and number.

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Snapshot Day 20 Year Report

We consolidated sites into waterbodies to portray frequent exceedance of ≥3 WQOs and classified them as Areas of Concern. Figure 3 shows the Areas of Concern for each year of sampling, although it is important to note that not all waterbodies are sampled each year due to lack of flowing water, funding or access. Areas of Concern for ≥10 years included the following 9 waterbodies: Watsonville Slough, Harkin Slough, Elkhorn Slough, Moro Cojo Slough, Tembladero Slough, Alisal Slough, Santa Rita Creek, Natividad Creek and the Reclamation Ditch. Sites and waterbodies that more frequently exceeded the WQOs of multiple parameters tended to be located in sub-watersheds with intensive agricultural or mixed agricultural and urban use. Of the 192 waterbodies monitored 5 or more years, 59 waterbodies were never listed as an Area of Concern over the years sampled.

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Snapshot Day 20 Year Report

Figure 3. Areas of Concern by waterbody were identified for each year the waterbody was sampled and exceeded three WQOs for analytes (nitrate, orthophosphate or E. coli) and field measures (dissolved oxygen, pH, water temperature, or clarity).

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Snapshot Day 20 Year Report

Nutrients at Sites Monitored ≥5 Years A total of 81 out of 192 sites (42%) monitored for ≥5 years on Snapshot Day did not exceed nutrient (neither nitrate nor orthophosphate) water quality objectives. A total of 128 out of 192 sites (67%) and 88 sites out of 192 (46%) showed no exceedance of the nitrate or orthophosphate WQO respectively. Six sites exceeded the nitrate WQO all the years monitored and one site exceeded the orthophosphate WQO every year sampled. Table 4 shows sites where either nitrate or orthophosphate exceeded the WQO 50% or more of the years monitored. All data is available in Appendix 1.A.

Table 4. Listing of the sites monitored for at least 5 years for nutrients and exceeding both WQOs at least once. Sites Monitored at Least 5 Years Nitrate as N Orthophosphate as P Max Percent Max Percent Concentr # Years Years Concentr # Years Years # Years ation Exceeded Exceeded # Years ation Exceeded Exceeded Site Code Site Name Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO 202-CALER-11 Calera Creek at Reina del Mar 17 1.7 1 6 16 0.16 1 6 202-CALER-12 Calera Creek near mouth 15 5.3 5 33 14 1.59 6 43 202-LOBIT-11 Lobitas Creek on Lobitos Creek Rd 18 1.54 1 6 18 0.18 2 11 202-MILLC-11 Mill Creek in Burliegh-Murray State Pa 16 1.78 1 6 15 0.19 2 13 202-PILAR-11 Pilarcitos Creek at Oak Ave 17 4.88 10 59 15 0.14 1 7 202-POMPO-11 Pomponio Creek mouth 18 1.2 1 6 17 0.21 2 12 202-SANGR-12 San Gregorio Creek at Stage Rd 11 8.46 1 9 10 0.23 2 20 202-SANGR-14 La Honda Creek 15 12.64 1 7 14 0.16 1 7 304-ARROY-22 Arroyo Creek at Delaware Ave 18 2.25 8 44 18 0.26 4 22 304-ARROY-23 Arroyo Creek at West Cliff Drive 18 3.81 17 94 17 0.18 1 6 304-LIDEL-21 Lidell Creek on Bonny Doon Road 20 1.34 3 15 20 1.34 12 60 304-MOLIN-21 Molino Creek at Swanton Road 14 1.07 1 7 14 0.28 5 36 304-ROBSC-21 Rob's Creek along 34th Avenue 10 2.21 3 30 10 0.12 1 10 304-SCSD-02 Santa Cruz storm drain on Merced Ave 12 4.42 12 100 12 0.14 1 8 304-SCSD-04 Santa Cruz storm drain on Woodrow A 14 4.25 14 100 14 0.12 1 7 305-BEACH-21 Beach Road Ditch at Palm Beach 16 60.1 15 94 16 1.29 3 19 305-HARKI-22 Harkins Slough at PVWMA Pump 15 11.83 7 47 15 0.38 8 53 305-HARKI-23 Harkins Slough at Buena Vista Dr 17 2.4 3 18 17 0.31 2 12 305-PAJAR-21 Pajaro River @ Thurwachter Bridge 19 12 14 74 5 0.2 1 20 306-ELKHO-31 Elkhorn Slough at Kirby Park 10 1.12 1 10 12 0.22 2 17 306-ELKHO-32 Elkhorn Slough at Hudson's Landing 17 16.2 6 35 17 0.18 2 12 306-ELKHO-34 Elkhorn Slough at Garin Road 18 48.2 15 83 18 4.26 10 56 306-MOROC-31 Moro Cojo Slough upper 18 37 15 83 6 2.4 4 67 306-MOROC-34 Castroville Slough us Moro Cojo Sloug 6 8.7 1 17 6 0.4 3 50 309-ALISA-32 Alisal Creek upper 20 52.9 19 95 20 1.68 20 100 309-ASILO-31 Asilomar State Park at bridge 19 1.22 2 11 19 0.18 1 5 309-CENTR-31 Greenwood Park at Central and 13th S18 5.77 16 89 18 0.46 4 22 309-DOLPH-31 Dolphin Brook @ Van Buren Street 9 1.38 3 33 9 0.18 2 22 309-GABIL-31 Gabilan Creek at Independence Rd 14 30.7 14 100 14 0.6 7 50 309-NATIV-31 Natividad Creek at Las Casitas Rd 17 48.1 14 82 17 1 14 82 309-RECDI-31 Reclamation Ditch at Davis Rd 18 39.8 18 100 18 0.94 15 83 309-SALIN-31 Salinas River at Gypse Camp 19 40.05 19 100 19 0.27 10 53 309-SALIN-32 Salinas River at Davis Rd 18 23.9 15 83 18 0.28 6 33 309-SALIN-33 Salinas River at Chualar Bridge 16 6.2 7 44 16 0.1 2 13 309-SRITA-34 Santa Rita Creek at Russell Rd 12 54 6 50 5 0.4 5 100 309-SRITA-35 Santa Rita Creek at Van Buren Ave 12 314 7 58 5 1.4 3 60 309-TEMBL-31 Tembladero Slough at Monterey Dune 19 60.5 16 84 6 0.45 4 67 309-TEMBL-32 Tembladero Slough Hwy 183 19 53.5 16 84 6 0.4 2 33 309-TEMBL-33 Tembladero Slough @ Preston Bridge 16 74.7 15 94 6 0.5 5 83 309-UPPER-31 Natividad Creek upper 16 68.3 13 81 16 1.07 13 81 310-SANSI-41 San Simeon Creek at campground 17 13 10 59 17 1 8 47 310-SYB-41 Santa Ysabela Creek on Turri Road 15 11 9 60 15 0.32 6 40 310-UCF-41 Upper Chorro Flats at Chorro Creek Rd 15 3.8 11 73 15 0.59 12 80

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Snapshot Day 20 Year Report

Sites were organized into 9 major watersheds, also called hydrologic units (HUs) to better evaluate water quality on a scale such that a community could focus efforts to bring about improvements (Fig. 2a-2c). The first three digits of site labels indicate the HU: San Mateo (202), Big Basin (304), Pajaro (305), Elkhorn Slough (306), Carmel (307), Santa Lucia (308), Salinas (309), Estero Bay (310) and Estrella (317). Only the Carmel HU showed no exceedance of the nitrate WQO at any site over all the years monitored; however Carmel did exhibit orthophosphate exceedances. Carmel’s Hatton Canyon site (307-HATTO-31) exceeded the orthophosphate WQO 4 out of 8 years (50%). The Santa Lucia HU had a low incidence of exceedance of the nitrate WQO, however six sites (27%) exceeded the orthophosphate WQO at least once and up to 30% of the years monitored. Five of the 9 HUs monitored had sites that exceeded the nitrate WQO more than 60% of the years monitored. Fewer sites in the Salinas watershed repeatedly exceeded the WQO compared with the Snapshot Day Multi- Year Report (Krone et al. 2015); however the revised WQO targets in the Basin Plan are the primary reason, rather than real improvements in water quality. In four of the HUs (San Mateo, Carmel, Santa Lucia, Estrella) no sites exceeded the nitrate WQO more than 60% of the years monitored (Appendix 1.A and Fig. 4).

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Snapshot Day 20 Year Report

Figure 4. Percentage of years that sites within a watershed exceeded water quality objectives (WQOs) for nitrate- N and orthophosphate-P. Only sites monitored ≥5 years were analyzed. The Estrella watershed was omitted because only 1 site was monitored ≥5 years.

E. coli at Sites Monitored ≥5 Years The E. coli WQO was exceeded at a higher frequency than the nutrient WQOs. Out of the 192 sites monitored for E. coli for ≥5 years, 155 sites (81%) exceeded the 235 MPN/100 mL WQO at least once.

The following 8 sites exceeded the E. coli WQO every year: Greenwood Park at Central (309-CENTR- 31), Santa Rita Creek at Bellizona (309-SRITA-32), 14th hole Salinas Valley Golf Course (309-SRITA-33), Santa Rita Creek at Russell Road (309-SRITA-34), Santa Rita Creek at Van Buren Avenue (309-SRITA-35), Upper Natividad Creek at E. Boronda Road (309-UPPER-31), San Bernardo Creek (310-SBE-41), and Pilkington Creek at Forbes Road (304-PILKI-21). Many of these sites are in high density urban areas although some are in low density developed areas mixed with agriculture. Notably, the four sites on Santa Rita Creek in Salinas (309-SRITA-32, 309-SRITA-33, 309-SRITA-34, 309-SRITA-35) are in areas where pastured animals, pets or failing septic systems may be the source of the issue.

All HUs demonstrated repeated exceedance at some sites, although Carmel, Santa Lucia and Estrella HUs did not have any sites that exceeded the WQO more than 60% of the years sampled (Fig. 5). All sites monitored five or more years in the Pajaro, Elkhorn, and Salinas watersheds exceeded the E. coli WQO at least one year.

Figure 5. Percentage of years that sites within a watershed exceeded water quality objectives (WQOs) for E. coli (235 MPN per 100 mL). Only sites monitored ≥5 years were analyzed. The Estrella watershed was omitted because only 1 site was monitored ≥5 years.

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Snapshot Day 20 Year Report

Field Measured Water Chemistry Parameters Field measurements (pH, dissolved oxygen, water temperature, turbidity, and water clarity) conducted at the sites were compared with the WQO for all years monitored. A total of 24 out of 192 sites (13%) monitored for ≥5 years did not exceed any of the field parameter WQOs during all Snapshot Day events. The HUs with sites where no exceedance of any field measured water chemistry parameters are identified in Table 5. Four HUs (Pajaro, Elkhorn Slough, Salinas, and Estrella) had at least one field parameter WQO exceeded at a site over all the years monitored. This is important information, especially because samples are only collected annually, but over the course of 20 years, a pattern may emerge and indicate potential chronic impairment that should be investigated. All data is available in Appendix 1.B.

Table 5. The HU for Snapshot Day sites that never exceeded the WQO for any field measurement during all the years they were monitored.

Total # Sites Total # Sites with no % of Sites HU Watershed Monitored for Exceedance of WQO with No Field at Least 5 Years for Field Measures Exceedance 202 San Mateo 30 5 17 304 Big Basin 58 7 12 305 Pajaro 13 0 0 306 Elkhorn Slough 8 0 0 307 Carmel 8 0 0 308 Santa Lucia 23 6 26 309 Salinas 34 0 0 310 Estero Bay 16 3 19 317 Estrella 1 0 0

The WQO for dissolved oxygen (DO) is a range from 7 to 12 mg/L. The range of DO observed over all Snapshot Day events was between 0.78 mg/L to 19 mg/L, with 523 out of 2607 samples (20 %) falling below the minimum and 23 samples (<1%) above the maximum WQO for sites monitored 5 years or more. DO was the most commonly exceeded parameter with 147 out of 192 (77%) sites falling outside the WQO range at least one year and 14 out of 192 (7%) of sites outside of range more than 60% of the time. Five sites (Moore Creek at Empire Grade Rd. (304-MOORE-22), Watsonville Slough at Harkins Slough Rd. (305-WATSO-21), Leona Creek between Salerno and Pompeii Rds. (304-LEONA-21), Pilkington Creek at Forbes Rd. (304-PILKI-21) and Yerba Buena Creek at Estrada Avenue (309-YERBA-41) were outside the WQO range for dissolved oxygen >80% of the years monitored.

All 9 HUs had one or more sites that exceeded the dissolved oxygen WQO by falling either below the lower limit or above the upper limit (Fig. 6). Big Basin, Pajaro, Salinas and Elkhorn Slough HUs all had sites that exceeded the dissolved oxygen WQO more than 80% of the years monitored: Big Basin 3 out of 58 sites (5.2% ), Pajaro 1 out of 13 sites (7.7% ), Salinas 1 out of 33 sites (3%) and Elkhorn Slough 1 out of 8 (12.5%).

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Snapshot Day 20 Year Report

Water temperature was measured above the WQO of 21⁰ C for 95 out of a total of 2659 temperature measurements (3.6%) taken over all Snapshot Day events. The maximum observed water temperature of 30⁰ C was on May 7, 2005 at Moro Cojo Slough Lower at Hwy 1 (306-MOROC-33). Of the sites monitored for more than five years, 158 out of 192 sites (82%) never had an exceedance of the temperature WQO during Snapshot Day monitoring. No sites exceeded the WQO more than 80% of the time. The two sites with the most frequent exceedance of WQO were Santa Rita Creek at Van Buren Avenue (309-SRITA-35) and Moro Cojo Slough at Castroville Slough (306-MOROC-32) with temperature measurements above 21⁰ C for 9 out of 12 years (75%) and 7 out of 12 years (58%), respectively. Two HUs (Carmel and Santa Lucia) did not have any sites monitored for at least 5 years that exceeded the water temperature WQO (Fig. 6).

The WQO for pH is a range between 6.5 and 8.5. The range of pH observed during Snapshot Day monitoring was between 4.7 to 9.9 over the total of 2683 samples taken. The results for pH fell below the WQO for 112 (4.1%) samples and above for 43 (1.6%) samples. The two sites out of range most frequently were Moro Cojo Slough at Castroville Slough Confluence (306-MOROC-32) where pH measured >8.5 for 11 out of 13 years (85%) and Moro Cojo Slough Lower at Hwy 1 (306-MOROC-33) where pH measured >8.5 for 12 out of 14 (86%) years. Both of these sites are in the Elkhorn Slough HU, where 2 out of 7 sites (29%) exceeded the WQO for more than 80% of the years monitored. None of the HUs had all sites within the pH range for all the years monitored (Fig. 6).

Figure 6: Percentage of years that sites within a watershed exceeded water quality objectives (WQOs) for field measured water chemistry. Only sites monitored ≥5 years were analyzed. The Estrella watershed was omitted because only 1 site was monitored ≥5 years.

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Snapshot Day 20 Year Report

Turbidity and tranparency are both measures of light penetration of the water column and both measures relate to the amount of suspended particles in the water (USEPA 1997). Field measurements of either transparency or turbidity were taken at many sites from 2000 through 2019, however only one of the two measures, and not both, were taken at the same site each year. Furthermore, the same measure was not consistently taken at a particular site each year, thus some years turbidity was measured at a site and other years transparency was measured at the same site. The Snapshot Day turbidity measurements were taken with turbidity meters whereas transparency measurements were taken with a transparency tube. However despite the different methods used, the two measures are both indicators of the same water quality problem with the same potential water quality issues: lower production of dissolved oxygen, clogging of fish gills, smothering of fish eggs and macro-invertebrates as particles settle (USEPA 1997). Therefore, we have combined the two measures into “water clarity” and displayed the number of sites exceeding the WQO for each watershed in terms of the percent of years these WQOs were exceeded (Fig. 7). There is no universally applicable formula to translate one value to the other, as multiple studies have found different relationships exist between waterbodies (MPCA 2005, Myer & Shaw 2006, Fermanich 2006). As no comparative studies between values have been conducted on the Central Coast, we adopted the WQO of not to exceed 25 NTU for turbidity and no less than 25 cm for transparency. The decision to use these numerics is based on choosing the mid- range between findings from other studies showing the turbidity measures of 25 NTU can translate in some streams to a water clarity measures of 20 cm and in other cases to water clarity of 30 cm (MPCA 2005, Myer & Shaw 2006, Fermanich 2006).

Figure 7. Percentage of years that sites within a watershed exceeded water quality objectives (WQOs) for turbidity or transparency, in combination referred to as ‘water clarity’. Only sites monitored ≥5 years were analyzed. The Estrella watershed was omitted because only 1 site was monitored ≥5 years.

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Snapshot Day 20 Year Report

A total of 548 measures of turbidity and 1341 measures of water clarity were taken over all Snapshot Day events, with an incidence of 45 measurements (8.2%) above the turbidity WQO of 25 NTU and 194 measurements (14.5%) below the transparency WQO of 25 cm. The highest turbidity measured was 385 NTU at Salsipuedes Creek at East Lake Avenue Bridge (305-SALSI-21) on May 21, 2004. A number of sites had water clarity measured at less than 2 cm for one or more years: Butano Creek at Pescadero Rd. (202-BUTAN-11), Moore Creek at the outflow of Antonelli Pond (304-MOORE-21), Upper Moro Cojo Slough (306-MOROC-31), Moro Cojo Slough at Castroville Slough Confluence (306-MOROC-32), Rocky Creek (308-ROCKY-31), Paso Robles Creek at Santa Rita Road (309-PASOR-41), Santa Rita Creek at Bellizona (309-SRITA-32), 14th hole Salinas Valley Golf Course (309-SRITA-33), Santa Rita Creek at Russell Road (309-SRITA-34), and Santa Rita Creek at Van Buren Avenue (309-SRITA-35).

Each HU had at least one site that exceeded the WQO for water clarity for one or more years. The following HUs had sites that exceeded the water clarity (combining the measures of turbidity and transparency) WQOs for more than 80% of the years monitored: San Mateo at 10 out of 24 sites (42%), Big Basin at 14 out of 45 sites (31 %), Pajaro at 2 out of 12 sites (17%), Elkhorn Slough at 2 out of 7 sites (29%), Salinas at 6 out of 34 sites (18%), and Estero Bay at 5 out of 14 sites (36%).

3.2. STATISTICS - TRENDS

Three analytes of special concern (nitrate, orthophosphate and E. coli) were evaluated for trends using the Mann-Kendall test and the calculation of an Arkitas-Sen-Theil slope, provided data were available for ≥5 years at a site and there was at least one exceedance of the WQO.

Nutrient Trends

A total of 192 sites were monitored for ≥5 years and of these the nitrate-N WQO was exceeded at least once at 71 sites (Fig. 8). Of the 71 sites evaluated, a trend in nitrate concentration was detected at 11 sites based on the Mann-Kendall trend test and a p-value of 0.10, with 5 improving water quality and 6 worsening water quality (Table 5, Fig. 8). If instead we use a more conservative p-value of 0.05, the trend test results show trends at 6 sites, four improving and two worsening. The steepest worsening trend for nitrate was detected at a site in the Salinas HU on Tembladero Slough at Hwy 183 (309- TEMBL-32, slope = 2.42 mg/L-yr, p-value < 0.01). Because of the low p-value and because both the upper and lower 95% confidence intervals (CIs) were positive, showing an increase in concentration, our confidence is very high that a trend existed at this site between 2000 and 2019. The nitrate-N concentration at this site for the first three years starting in 2000 was below the WQO and in 2015 was measured at 53.5mg/L. Harkins Slough (305-HARKI-22, slope = -0.08 mg/L-yr, p-value < 0.01) demonstrated a declining trend indicating improving water quality and with both CIs negative or zero, providing a high level of confidence for a declining concentration trend at this site. At sites where the CIs fell above and below zero, there is some ambiguity. A longer monitoring period may help distinguish and lend confidence regarding whether a trend actually occurred at these sites.

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Snapshot Day 20 Year Report

Figure 8. Map of sites monitored more than 5 years showing Nitrate trends, both improving and worsening.

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Snapshot Day 20 Year Report

Table 5. Results of the Mann-Kendall trend test for sites with a p-value ≤ 0.10. Also shown are the Arkitas-Sen-Theil slope along with the upper and lower 95% CIs for this slope. When the two CIs are both either positive or negative, this provides increased confidence that a trend existed. Bold lettering is used when both 95% CIs are directionally consistent.

Nitrate as N Number Slope Lower Slope Upper Years A-K-T Slope 95% Confidence 95% Confidence Site Code Site Sampled tau p-value (mg/L-yr) Interval Interval Trend 304-LIDEL-21 Lidell Creek on Bonny Doon 20 -0.32 0.05 -0.04 -0.06 0.01 Improving 304-SCSD-03 Santa Cruz storm drain 11 -0.71 0 -0.06 -0.12 -0.02 Improving 305-CORRA-21 Corralitos Creek 16 0.32 0.1 0.05 -0.25 0.15 Worsening 305-HARKI-22 Harkins Slough 15 -0.33 0.09 -0.08 -0.8 0 Improving 309-ALISA-32 Alisal Creek upper 20 0.35 0.03 0.90 -0.1 1.99 Worsening 309-DOLPH-31 Dolphin Brook 9 -0.69 0.01 -0.12 -0.22 -0.01 Improving 309-NATIV-31 Natividad Creek 17 0.34 0.06 0.93 -0.1 2.16 Worsening 309-TEMBL-31 Tembladero Slough 19 0.3 0.07 1.30 -0.19 2.63 Worsening 309-TEMBL-32 Tembladero Slough Hwy 183 19 0.63 0 2.42 1.28 3.69 Worsening 309-UPPER-31 Natividad Creek upper 16 0.32 0.1 1.60 -0.21 2.71 Worsening 310-UCF-41 Upper Chorro Flats 15 -0.4 0.04 -0.10 -0.22 0.05 Improving

Figure 9. Three trend lines for nitrate-N concentration over the period of Snapshot Day observations are shown along with the 95% CIs.

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Snapshot Day 20 Year Report

We further investigated the increasing nitrate trend observed at Tembladero Slough at Hwy 183 (309- TEMBL-32) by comparing concentrations to other sites monitored on the Tembladero Slough. The three sites are shown in Figures 10 and 11 are within three miles of one another, with Tembladero Slough at Molera Road (309-TEMBL-31) furthest downstream and closest to the ocean and Tembladero Slough at Hwy 183 (309-TEMBL-32) furthest upstream. In some years there was considerable variability in nitrate-N concentrations across the three sites. The highest variation (61.3 mg/L) between sites was observed in 2013 when the furthest downstream site nitrate-N concentration at Tembladero Slough at Molera Road (309-TEMBL-31) was 13.4 mg/L while the furthest upstream concentration at Tembladero Slough at Hwy 183 (309-TEMBL-32) was 51.6 mg/L and the middle site at Tembladero Slough at Preston Street Bridge (309-TEMBL-33) had a concentration of 74.7 mg/L. A similar pattern was observed in 2011 with the highest concentration occurring at the middle site and the lowest concentration at the furthest downstream site. However this pattern was not consistent. During other years (2009, 2010, 2012) the highest concentration was observed at the furthest upstream site 309-TEMBL-32 and lower concentrations at the two downstream sites. This localized concentration and high variability along the waterway may be due to the many sources of runoff from irrigated lands along the extent of the channel.

3.5 miles

Figure 10. Tembladero Slough sites, although within a 3 mile scope, sometimes have large variability in nitrate-N concentrations, up to a 61.3 mg/L difference between sites.

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Snapshot Day 20 Year Report

Figure 11. The location of the three sites monitored on Tembladero Slough and the nitrate concentrations measured at each site are shown in the above map and plot. There is considerable variability in concentrations between sites in the same year even though they are within 3 miles of one another, notice 2011 and 2013.

Of the 192 sites monitored for 5 or more years, the orthophosphate as P WQO was exceeded at least once at 93 sites (Fig. 12 and 13). Of the 93 sites where a trend test was conducted, 9 sites (10%) demonstrated a trend in orthophosphate as P concentrations when a p-value of 0.10 was used for significance and 7 sites (8%) when a p-value of 0.05 was used (Table 6). In our 2014 multi-year report, all trends for orthophosphate were showing trends toward improving, so seeing 4 worsening trends is disappointing.

Table 6. Results of the Mann-Kendall trend test and A-K-T slope for orthophosphate found trends in 10% of sites monitored for at least 5 years. Bold lettering is used when both 95% CIs are directionally consistent.

Orthophophate as P Number Slope Lower Slope Upper Years A-K-T Slope 95% Confidence 95% Confidence Site Code Site Sampled tau p-value (mg/L-yr) Interval Interval Trend 304-BRANC-25 Branciforte Creek at 4055 Bra19 0.51 0.04 0.012 -0.01 0.02 Worsening 304-MOORE-26 Moore Creek at mouth 6 0.31 0.08 0.002 0 0.01 Worsening 305-HARKI-22 Harkins Slough at Pajaro Vall 15 -0.46 0.02 -0.019 -0.03 -0.01 Improving 306-ELKHO-34 Elkhorn Slough at Garin Road 17 -0.61 0 -0.058 -0.17 -0.03 Improving 309-ATASC-41 Atascadero Creek at West M 18 -0.38 0.05 -0.003 -0.01 0 Improving 309-SALIN-45 Salinas River at Old Hwy 58 B 18 0.36 0.04 0.002 0 0.01 Worsening 309-SKYLI-31 Skyline at Forest Knoll Road 15 0.47 0.09 0.015 0 0.04 Worsening 309-TROUT-41 Trout Creek at 3 bridges 16 -0.69 0 -0.018 -0.02 -0.01 Improving 310-SYB-41 Santa Ysabela Creek on Turri 17 -0.48 0.01 -0.01 -0.02 0 Improving

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Snapshot Day 20 Year Report

Figure 12. Map of sites monitored more than 5 years showing Orthophosphate trends, both improving and worsening.

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Snapshot Day 20 Year Report

Figure 13. Trends for orthophosphate-P trends observed for Snapshot Day sites. Results below the minimum detection limit are plotted as short vertical dashed lines along the x-axis.

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Snapshot Day 20 Year Report

E. coli Trends

Of the 192 sites monitored for ≥5 years for E. coli, 125 sites exceeded the WQO at least once (Fig. 14 and 15). Twenty of these sites demonstrated trends for E. coli when a p-value of 0.10 was used for significance, with 14 declining trends, indicating improved water quality, and 6 increasing trends, indicating worsening water quality (Table 7). When a p-value of 0.05 was used for significance, 11 sites showed trends, 6 improving and 5 worsening.

Table 7. Results of the Mann-Kendall trend test for E coli found improving water quality at 14 sites. Bold lettering is used when both 95% CIs are directionally consistent.

Escherichia coli Number Slope Lower Slope Upper Years A-K-T Slope 95% Confidence 95% Confidence Site Code Site Sampled tau p-value (mg/L-yr) Interval Interval Trend 202-DEERC-12 Deer Creek behind Creekside 9 0.56 0.05 406.432 37.58 3436.08 Worsening 202-LAHON-11 San Gregorio Creek at La Hon 16 -0.450.02 -25.59 -60.96 -1.3 Improving 202-MONTA-11 Montara Creek upstream at D15 -0.32 0.1 -20.313 -44.88 14.49 Improving 202-PESCA-11 Pescadero Creek at Stage Ro 17 -0.32 0.07 - 4.605 -23.97 0 Improving 202-POMPO-11 Pomponio Creek mouth 16 -0.32 0.09 -17.373 -50.37 5.33 Improving 202-SANGR-12 San Gregorio Creek at Stage 10 -0.580.02 -59.496 -348.43 0 Improving 202-WHITE-12 Whitehouse Creek mouth 14 -0.35 0.09 -4.362 -14.85 0.83 Improving 304-ARANA-23 Arana Creek at Paul Sweet Ro 12 -0.47 0.04 -26.845 -122.84 -2.2 Improving 304-ARROY-21 Arroyo Creek at Meder Park 18 -0.46 0.01 -12.355 -22.78 -5.99 Improving 304-SCSD-04 Santa Cruz storm drain on W14 -0.38 0.06 -94.457 -311.91 -3.45 Improving 305-HARKI-22 Harkins Slough at Pajaro Vall 15 0.39 0.05 14. 333 2.69 568.97 Worsening 305-STRUV-22 Struve Slough at Lee Road M 17 -0.380.03 -16.928 -8.9 1.1 Improving 305-WATSO-23 Watsonville Slough at Palm B17 -0.330.07 -14.416 -32.15 10.43 Improving 308-SANJO-31 San Jose Creek at Hwy 1 17 -0.32 0.08 -5.819 -14.97 1.89 Improving 309-ASILO-31 Asilomar State Park at bridge 19 -0.49 0 -30.483 -80.09 -9 Improving 309-GABIL-31 Gabilan Creek at Independen 14 0.42 0.04 35.032 -11.88 126.7 Worsening 309-SALIN-31 Salinas River at Gypse Camp 19 0.29 0.09 5.464 1.99 16.82 Worsening 309-SALIN-33 Salinas River at Chualar Bridg 16 0.42 0.02 3.88 0.43 9.48 Worsening 310-LAGUN-41 Arroyo Laguna mouth 11 0.55 0.02 190.109 39.61 918.91 Worsening 317-ESTRE-43 Estrella River at Whitley Gar 8 0.57 0.06 219.015 2.75 1908.48 Worsening

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Snapshot Day 20 Year Report

Figure 14. Map of sites monitored more than 5 years showing E.coli trends, both improving and worsening.

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Snapshot Day 20 Year Report

Figure 15. Trends for E. coli concentration at the three sites.

3.3. COMPARISON OF CCAMP AND SNAPSHOT DAY TRENDS AND RATING

Sites that CCAMP has identified as impacted or severely impacted are of highest concern for aquatic life according to various indices that include chemistry, biology and physical habitat data (SWAMP 2014). These sites are shown in Tables 8 thru 11 to provide the reader the opportunity to compare Snapshot Day results with CCAMP results. The CCAMP rating is an overall aquatic health rating and Snapshot Day relates the percent of years the single analyte WQO was exceeded, with no attempt to rate aquatic health. The rating comparison between the overlapping CCAMP and Snapshot Day sites for nitrate, orthophosphate and E. coli showed a good level of coincidence between the two programs despite the difference in sampling regimes and years sampled (see methods). Overlapping sites that were not monitored for ≥5 years during Snapshot Day or were not rated by CCAMP, were not included in this comparison

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Snapshot Day 20 Year Report

Nitrate as N We compared CCAMP ratings and Snapshot Day WQO exceedances for nitrate-N and found that sites with an excellent, good or fair CCAMP rating had exceedances between 0 -13% of the years monitored during Snapshot Day. The sites rated as severely impacted for nitrate-N had exceedances ranging between 58-100% of the years monitored during Snapshot Day (Table 8).

Table 8. Comparison of the CCAMP rating at overlapping sites with the range of percent of years sites monitored during Snapshot Day exceeded the Water Quality Objective (WQO) Nitrate-N Orthophosphate-P E. Coli

Number Number Number SSD % Years Overlapp SSD % Years Overlapp SSD % Years Overlapping Exceeded ing Sites Exceeded ing Sites Exceeded CCAMP Rating Sites Sites WQO Sites WQO CCAMP Rating Sites WQO Excellent 23 0-13% 5 0-7% Top Quartile 8 0-33% Good 2 0% 8 0-7% Fair 3 0-10% 7 0-36% Second Quartile 6 11-87% Impacted 7 0-53% Severely Impacted 8 58-100% 10 0-83% Bottom Quartile 8 20-100%

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Snapshot Day 20 Year Report

Table 9. Sites rated by the CCAMP as impacted or severely impacted for nitrate contamination demonstrated a high percent of years the WQO was exceeded during Snapshot Day monitoring.

Nitrate

Snapshot % Years TYPE CCAMP Snapshot Day Site Name Day Date Snapshot Day Exceeded CCAMP Date Site Code Range Trend SSD WQO Site Code Range CCAMP Trend CCAMP Rating 202-GAZOS-11 Gazos Creek at mouth 2000-2018 no change 0 CC 304GAZ 2001-2015 no change excellent 304-APTOS-21 Aptos Creek at steel bridge in Nisene Ma2000-2013 no change 0 W 304APS 2005-2011 no change excellent 304-APTOS-23 Aptos Creek at mouth 2001-2019 no change 0 W 304APW 2001-2002 no change good 304-ARANA-21 Arana Creek at Harbor High fish ladder 2001-2019 no change 0 W 304ARA 2005-2011 no change good 304-SANLO-27 San Lorenzo River at Junction Park 2005-2019 no change 0 W 304SLE 2005-2011 no change excellent 304-SCOTT-25 Scott Creek at Hwy 1 2006-2019 no change 0 CC 304SCO 2001-2015 no change excellent 304-SOQUE-21 Soquel Creek At Nob Hill 2000-2011 no change 0 CC 304SOK 2005-2015 no change excellent 304-SOQUE-22 Soquel Creek At Mouth 2001-2019 no change 0 CC 304SOQ 2001-2004 no change excellent 305-HARKI-21 Harkins Slough at Harkins Slough Rd. 2000-2018 no change 0 W 305HAR 2005-2011 no change excellent 305-PAJAR-21 Pajaro River under Thurwachter Bridge 2000-2018 no change 74 CC 305THU 1997-2015 Improving severely impacted 305-STRUV-22 Struve Slough at Lee Rd. 2001-2019 no change 0 W 305STL 2005-2011 no change NR 305-WATSO-22 Watsonville Slough at Pajaro Valley Wat2001-2019 no change 69 W 305WSA 2005-2015 Worsenning severely impacted 306-ELKHO-31 Elkhorn Slough at Kirby Park 2004-2016 no change 10 W 306ELK 1999-2012 no change fair 306-MOROC-33 Moro Cojo Slough Lower at Hwy 1 2001-2019 no change 11 W 309MOR 1999-2015 no change fair 307-CARME-33 Carmel River at Rosie's Bridge 2000-2019 no change 0 W 307CMU 2002-2015 no change excellent 307-CARME-36 Carmel River at Schulte Rd. 2000-2019 no change 0 W 307CMD 2002-2015 no change excellent 307-CARME-38 Carmel River at Hwy 1 2000-2019 no change 0 W 307CML 2001-2015 no change excellent 308-BIGCR-31 Big Creek at Hwy 1 2002-2013 no change 0 W 308BGC 2001-2015 Improving excellent 308-BIGSU-31 Big Sur River at &rew Molera Park 2000-2019 no change 0 W 308BSR 2001-2015 Worsenning excellent 308-GARRA-31 Garrapata Creek 2001-2019 no change 0 W 308GAR 2002-2015 no change excellent 308-LIMEK-31 Limekiln Creek at Hwy 1 2002-2019 no change 0 W 308LIM 2002-2015 no change excellent 308-MILLC-31 Mill Creek at Hwy 1 2002-2013 no change 0 W 308MIL 2002-2015 no change excellent 308-WILLO-31 Willow Creek at mouth 2002-2013 no change 0 W 308WLO 2001-2015 no change excellent 309-ATASC-41 Atascadero Creek at West Mall Bridge 2001-2019 no change 0 W 309ATS 1999-2012 no change excellent 309-SALIN-31 Salinas River at Gypse Camp 2001-2019 no change 100 W 309SBR 1999-2012 no change severely impacted 309-SALIN-32 Salinas River at Davis Rd. 2001-2019 no change 83 W 309DAV 1999-2015 Worsenning severely impacted 309-SALIN-44 Salinas River at Curbaril Bridge 2001-2018 no change 0 W 309SAT 1999-2012 no change fair 309-SALIN-47 Salinas River at 13th St bridge in Paso Ro 2000-2013 no change 0 W 309PSO 1999-2012 no change excellent 309-SRITA-35 Santa Rita Creek at Van Buren Avenue 2007-2018 no change 58 W 309RTA 2006-2014 no change severely impacted 309-TEMBL-31 Tembladero Slough at Molera Rd. 2001-2019 Worsening 84 W 309TDW 2001-2015 Worsenning severely impacted 309-TEMBL-33 Tembladero Slough at Preston St bridge 2004-2019 no change 94 W 309TEM 1999-2012 no change severely impacted 310-ARROY-42 Arroyo de la Cruz under Hwy 1 2001-2019 no change 0 W 310ADC 2001-2015 no change excellent 310-PICOC-41 Pico Creek under Hwy 1 bridge 2001-2019 no change 0 W 310PCO 2002-2015 no change excellent 310-SANSI-41 San Simeon Creek at campground bridge2001-2019 no change 59 W 310SSC 2001-2015 Worsenning severely impacted 310-SANTA-42 Santa Rosa Creek at Ferrasci Rd 2001-2019 no change 0 W 310SRU 2002-2015 no change excellent 310-SANTA-43 Santa Rosa Creek at Windsor St 2002-2019 no change 0 W 310SRO 2001-2015 Worsenning excellent 317-ESTRE-43 Estrella River at Whitley Gardens 2004-2012 no change 13 W 317ESE 2000-2012 no change excellent

* Type: W is for watershed sites and CC for Coastal Confluence sites in CCAMP. Note the difference in sampling regimes in the Methods section of this report.

The comparison of the trend tests for CCAMP data with Snapshot Day data also showed coincidence between the findings of the two programs at overlapping sites, although not always. For some overlapping sites a trend analysis was not conducted by one of the programs, usually due to an insufficient sample size. Of the 37 overlapping sites compared for nitrate-N trends, CCAMP did not observe a trend at 32 sites and Snapshot Day did not at 36 sites. Thus 32 of the same sites were identified as “no change” or not having a trend by both programs. The greater number of “no trend” sites statistically observed from Snapshot Day data can be partially explained by the lower number of samples due to only sampling on an annual basis. With less samples, a Type 2 error is more likely, where a trend may exist but could not be determined given the small sample size. Additionally, CCAMP may have found a trend where Snapshot Day data did not due to seasonal differences, for example seasons when increased fertilization rates take place or when runoff is more highly influenced by storm

January 2020 34

Snapshot Day 20 Year Report events. There were no trends found at overlapping sites for Snapshot Day, whereas decreasing trends for nitrate-N were found at 4 sites for CCAMP and increasing trends at 6 CCAMP sites (Table 9). Both programs showed a worsening trend at Tembladero Slough at Molera Road (309-TEMBL-31).

Orthophosphate as P There was coincidence between Snapshot Day and CCAMP findings for water quality related to orthophosphate. All overlapping sites that exceeded the WQO for more than 40% of the years monitored by Snapshot Day were rated as impacted or severely impacted by CCAMP for orthophosphate. All overlapping sites that ever exceeded the WQO during Snapshot Day, with one exception, were rated by CCAMP as fair to severely impacted. Of the 13 overlapping sites rated as good or excellent by CCAMP for orthophosphate, 11 sites had no exceedances during Snapshot Day. However, there were 7 overlapping sites rated by CCAMP as impacted or severely impact where no exceedances of the WQO were found during Snapshot Day monitoring.

Table 10. Snapshot Day exceedances generally coincided with CCAMP ratings. Sites exceeding the WQP >40% of the years monitored received CCAMP ratings as impaired or severely impaired. Sites receiving good or excellent ratings by CCAMP had low percent or no exceedances during the period of Snapshot Day monitoring. Orthophosphate TYPE Snapshot % Years Snapshot Day Site Name Day Date Snapshot Exceeded CCAMP CCAMP Date CCAMP Site Code Range Day Trend SSD WQO Site Code Range Trend CCAMP Rating 202-GAZOS-11 Gazos Creek at mouth 2000-2018 no change 0 CC 304GAZ 2001-2015 Worsening impacted 304-APTOS-21 Aptos Creek at steel bridge in Nisene Marks State 2000-2013 no change 14 W 304APS 2005-2011 no change impacted 304-APTOS-23 Aptos Creek at mouth 2001-2019 no change 33 W 304APW 2001-2002 no change severely impacted 304-ARANA-21 Arana Creek at Harbor High fish ladder 2001-2019 no change 42 W 304ARA 2005-2011 no change severely impacted 304-SANLO-27 San Lorenzo River at Junction Park 2005-2019 no change 0 W 304SLE 2005-2011 no change fair 304-SCOTT-25 Scott Creek at Hwy 1 2006-2019 no change 0 CC 304SCO 2001-2015 Worsening impacted 304-SOQUE-21 Soquel Creek At Nob Hill 2000-2011 no change 0 CC 304SOK 2005-2015 Worsening severely impacted 304-SOQUE-22 Soquel Creek At Mouth 2001-2019 no change 7 CC 304SOQ 2001-2004 no change fair 305-HARKI-21 Harkins Slough at Harkins Slough Rd. 2000-2018 no change 18 W 305HAR 2005-2011 no change fair 305-PAJAR-21 Pajaro River under Thurwachter Bridge 2000-2018 no change 20 CC 305THU 1997-2015 Worsening impacted 305-STRUV-22 Struve Slough at Lee Rd. 2001-2019 no change 0 W 305STL 2005-2011 no change severely impacted 305-WATSO-22 Watsonville Slough at PVWMA Pump Station 2001-2019 no change 0 W 305WSA 2005-2015 no change severely impacted 306-ELKHO-31 Elkhorn Slough at Kirby Park 2004-2016 no change 17 W 306ELK 1999-2012 no change fair 306-MOROC-33 Moro Cojo Slough Lower at Hwy 1 2001-2019 no change 0 W 309MOR 1999-2015 Imrproving severely impacted 307-CARME-33 Carmel River at Rosie's Bridge 2000-2019 no change 0 W 307CMU 2002-2015 no change good 307-CARME-36 Carmel River at Schulte Rd. 2000-2019 no change 0 W 307CMD 2002-2015 no change excellent 307-CARME-38 Carmel River at Hwy 1 2000-2019 no change 0 W 307CML 2001-2015 no change good 308-BIGCR-31 Big Creek at Hwy 1 2002-2013 no change 0 W 308BGC 2001-2015 Worsening good 308-BIGSU-31 Big Sur River at &rew Molera Park 2000-2019 no change 0 W 308BSR 2001-2015 Worsening excellent 308-GARRA-31 Garrapata Creek 2001-2019 no change 0 W 308GAR 2002-2015 no change good 308-LIMEK-31 Limekiln Creek at Hwy 1 2002-2019 no change 7 W 308LIM 2002-2015 no change excellent 308-MILLC-31 Mill Creek at Hwy 1 2002-2013 no change 0 W 308MIL 2002-2015 no change excellent 308-WILLO-31 Willow Creek at mouth 2002-2013 no change 0 W 308WLO 2001-2015 Worsening good 309-ATASC-41 Atascadero Creek at West Mall Bridge 2001-2019 Improving 6 W 309ATS 1999-2012 no change fair 309-SALIN-31 Salinas River at Gypse Camp 2001-2019 no change 53 W 309SBR 1999-2012 no change impacted 309-SALIN-32 Salinas River at Davis Rd. 2001-2019 no change 33 W 309DAV 1999-2015 Worsening impacted 309-SALIN-44 Salinas River at Curbaril Bridge 2001-2018 no change 7 W 309SAT 1999-2012 no change good 309-SALIN-47 Salinas River at 13th St bridge in Paso Robles 2000-2013 no change 36 W 309PSO 1999-2012 no change fair 309-SRITA-35 Santa Rita Creek at Van Buren Avenue 2007-2018 no change 60 W 309RTA 2006-2014 no change severely impacted 309-TEMBL-31 Tembladero Slough at Molera Rd. 2001-2019 no change 67 W 309TDW 2001-2015 no change severely impacted 309-TEMBL-33 Tembladero Slough at Preston St bridge 2004-2019 no change 83 W 309TEM 1999-2012 no change severely impacted 310-ARROY-42 Arroyo de la Cruz under Hwy 1 2001-2019 no change 0 W 310ADC 2001-2015 no change excellent 310-PICOC-41 Pico Creek under Hwy 1 bridge 2001-2019 no change 0 W 310PCO 2002-2015 no change good 310-SANSI-41 San Simeon Creek at campground bridge 2001-2019 no change 47 W 310SSC 2001-2015 Worsening severely impacted 310-SANTA-42 Santa Rosa Creek at Ferrasci Rd 2001-2019 no change 0 W 310SRU 2002-2015 no change good 310-SANTA-43 Santa Rosa Creek at Windsor St 2002-2019 no change 0 W 310SRO 2001-2015 Worsening impacted 317-ESTRE-43 Estrella River at Whitley Gardens 2004-2012 no change 0 W 317ESE 2000-2012 no change fair

* Type: W is for watershed sites and CC for Coastal Confluence sites in CCAMP. Note the difference in sampling regimes in the Methods section of this report.

January 2020 35

Snapshot Day 20 Year Report

For some overlapping sites a trend analysis was not conducted by one of the programs, usually due to an insufficient sample size. The trend analysis for orthophosphate was performed on each data set at 37 overlapping sites. This analysis did not find a trend at 27 CCAMP and 36 Snapshot Day sites, thus there was agreement between the two trend analyses at 27 sites with both finding “no trend”. The CCAMP trend analysis for orthophosphate found 1 improving and 5 worsening trends, while 1 improving trend was found by Snapshot Day.

Once again, these differences in trend findings and a lower number of observed trends from Snapshot Day are partially due to the smaller sample set for Snapshot Day. Additional reasons for the differences could be that CCAMP monitoring may pick up seasonal differences, such as levels of nutrient application rates, seasons or storm water runoff. The differences could also be associated with random differences in nutrient levels that may vary temporally. As sampling accounts only for the concentration at an instant in time, differences could just be based on the randomness associated with the timing of that instant.

E. coli

CCAMP does not provide aquatic life ratings for E. coli, but instead provides comparisons between all sites based on quartiles. Evaluation of the water quality site ratings by CCAMP for E.coli were coincident with the percent of years the site exceeded the WQO on Snapshot Day (Table 11). For all overlapping sites rated in the bottom quartile by CCAMP, these same sites exceeded the E.coli WQO 20-100% of the years monitored by Snapshot Day. All sites rated in the top quartile by CCAMP had an E.coli WQO exceedance rate of 0-33% of the years monitored during Snapshot Day.

January 2020 36

Snapshot Day 20 Year Report

Table 11. Sites evaluated as impacted or severely impacted by CCAMP all exceeded the WQO for E. coli during at least half of the years sampled. Type

% Years Snapshot Day SSD Date Exceeded CCAMP Site CCAMP Date CCAMP Site Code Site Name Range Ecoli Trend SSD WQO Code Range Trend CCAMP Rating 202-GAZOS-11 Gazos Creek at mouth 2000-2017 no change 19 CC 304GAZ 2001-2015 none top quartile 305-STRUV-22 Struve Slough at Lee Rd. 2001-2019 Improving 6 CC 305STL 2005-2011 none top quartile 306-MOROC-33 Moro Cojo Slough Lower at Hwy 1 2000-2019 no change 11 W 309MOR 2006-2012 none second quartile 308-LIMEK-31 Limekiln Creek at Hwy 1 2001-2019 no change 6 W 308LIM 2009-2015 none top quartile 308-WILLO-31 Willow Creek at mouth 2001-2012 no change 0 W 308WLO 2005-2015 none top quartile 309-ATASC-41 Atascadero Creek at West Mall Bridge 2001-2019 no change 60 W 309ATS 2006-2012 none bottom quartile 304-APTOS-21 Aptos Creek at steel bridge in Nisene M2000-2009 no change 0 CC 304APS 2005-2011 none top quartile 304-ARANA-21 Arana Creek at Harbor High fish ladder 2001-2019 no change 63 CC 304ARA 2005-2011 none second quartile 304-SANLO-27 San Lorenzo River at Junction Park 2005-2019 no change 27 CC 304SLE 2005-2011 none second quartile 304-SCOTT-25 Scott Creek at Hwy 1 2006-2019 no change 0 CC 304SCO 2001-2015 none NR 304-SOQUE-21 Soquel Creek At Nob Hill 2000-2009 no change 30 CC 304SOK 2005-2015 Worsening second quartile 305-HARKI-21 Harkins Slough at Harkins Slough Rd. 2001-2019 no change 53 CC 305HAR 2005-2011 none bottom quartile 305-PAJAR-21 Pajaro River under Thurwachter Bridge 2000-2018 no change 22 CC 305THU 2005-2015 Improving NR 305-WATSO-22 Watsonville Slough upstream Harkins Sl 2001-2019 no change 25 CC 305WSA 2005-2011 none bottom quartile 306-ELKHO-31 Elkhorn Slough at Kirby Park 2001-2013 no change 18 W 306ELK 2006-2012 none top quartile 307-CARME-33 Carmel River at Rosie's Bridge 2001-2019 no change 0 W 307CMU 2009-2015 none top quartile 307-CARME-36 Carmel River at Schulte Rd. 2001-2019 no change 0 W 307CMD 2009-2015 none top quartile 307-CARME-38 Carmel River at Hwy 1 2001-2019 no change 6 W 307CML 2005-2015 none top quartile 308-BIGCR-31 Big Creek at Hwy 1 2001-2013 no change 0 W 308BGC 2005-2015 none top quartile 308-BIGSU-31 Big Sur River at &rew Molera Park 2001-2019 no change 0 W 308BSR 2005-2015 Worsening top quartile 308-GARRA-31 Garrapata Creek 2001-2019 no change 6 W 308GAR 2009-2015 none top quartile 308-MILLC-31 Mill Creek at Hwy 1 2001-2013 no change 0 W 308MIL 2002-2015 none top quartile 309-SALIN-31 Salinas River at Gypse Camp 2001-2019 Worsening 16 W 309SBR 2006-2012 none top quartile 309-SALIN-32 Salinas River at Davis Rd. 2001-2019 no change 17 W 309DAV 2005-2015 none bottom quartile 309-SALIN-44 Salinas River at Curbaril Bridge 2001-2018 no change 31 W 309SAT 2006-2012 none top quartile 309-SALIN-47 Salinas River at 13th St bridge in Paso Ro 2000-2013 no change 9 W 309PSO 2006-2012 none top quartile 309-SRITA-35 Santa Rita Creek at Van Buren Avenue 2007-2018 no change 100 W 309RTA 2006-2012 none bottom quartile 309-TEMBL-31 Tembladero Slough at Molera Rd. 2001-2019 no change 63 W 309TDW 2005-2015 none bottom quartile 309-TEMBL-33 Tembladero Slough at Preston St bridge 2004-2019 no change 87 W 309TEM 2006-2012 none second quartile 310-ARROY-42 Arroyo de la Cruz under Hwy 1 2001-2019 no change 33 W 310ADC 2005-2015 none top quartile 310-PICOC-41 Pico Creek under Hwy 1 bridge 2001-2019 no change 27 W 310PCO 2009-2015 none top quartile 310-SANSI-41 San Simeon Creek at campground bridge 2001-2019 no change 44 W 310SSC 2005-2015 none second quartile 310-SANTA-42 Santa Rosa Creek at Ferrasci Rd 2001-2019 no change 20 W 310SRU 2009-2015 none bottom quartile 310-SANTA-43 Santa Rosa Creek at Windsor St 2002-2019 no change 27 W 310SRO 2005-2015 none bottom quartile 317-ESTRE-43 Estrella River at Whitley Gardens 2004-2012 Worsening 63 W 317ESE 2006-2012 none NR * W is for watershed sites and CC for Coastal Confluence sites in CCAMP.

A trend analysis for E. coli was performed on both the CCAMP and Snapshot Day data sets at 35 overlapping sites. CCAMP observed 3 trends at overlapping site and Snapshot Day observed 2 trends; however not at the same site (Table 11). At 30 sites, agreement existed between the two analyses that “no trend” was found. The lack of coincidence between the two programs’ sites where a trend was observed (but not from both data sets) could be due to the variation in the sampling regimes between the two programs or to the highly variable E. coli concentrations commonly found in environmental data.

4. DISCUSSION

Volunteer environmental monitoring programs afford the public an opportunity to contribute to environmental decision-making, to constructively address their concerns about the environment, and to learn about the science and technology involved in a monitoring effort (Pfeffer and Wagenet 2007). The Network programs administered by MBNMS and Coastal Watershed Council staffs accomplish these ends and additionally provide data for regional decision-making while fostering community

January 2020 37

Snapshot Day 20 Year Report stakeholders that care about the health of the Sanctuary and its watersheds. Outreach strategies and training efforts are key to program success as these raise community awareness of the existence and importance of the sanctuary as well as providing a foundation of training, technology and protocols for reliable data that can be trusted and used by managers and researchers beyond the MBNMS organization. The Snapshot Day citizen monitoring program follows guidelines recommended for a successful citizen monitoring effort including starting with a question that the data will help answer, use of standardized methods for data collection, data validation, providing feedback to volunteers, and reporting results (Silvertown 2009, Bonney et al. 2009).

Over the twenty years of annual Snapshot Day sampling sufficient data have been collected to provide a basis for identifying sites that show repetitive exceedance (or not) of one or more water quality objectives (WQOs) and some indication of an increasing or decreasing trend in pollutant concentration. While it is beyond the scope of this effort to analyze the cause or source of pollutants entering local waterways, our analysis can help increase the awareness of citizens, agencies and NGOs of pollutants entering our waters at concentrations where ecological harm may occur. Concurring with many ecological studies, areas with greater land use influences from human development tend to exhibit lower water quality (D’Arcy & Frost 2001, Novotny & Olem 1994, Haycock & Muscutt 1995, Johnson et al. 1997, Meador & Goldstein 2003, Foley et al. 2005). Hydrologic Units (HU) with more human development including higher density urban areas, farming and ranching tended to have more sites that exceeded the WQOs for nutrients, E. coli and field measured water chemistry parameters. HUs with more undeveloped land and lower density development had a lower number of sites repeatedly exceeding WQOs. These findings corroborate the need for continued effort to reduce anthropogenic influences on aquatic ecosystems. We believe this can be accomplished through efforts to reduce the contribution of pollutants from humans and through conscientious design of conservation practices into urban and agricultural settings and processes (Lenat & Crawford 1994, Haycock & Muscutt 1995, D’Arcy & Frost 2001, Tong & Chen 2002, Allan 2004, Ice 2004, Prokopy et al. 2008, Wong & Brown 2009).

Due to the small Snapshot Day sample size for each site (n = 5-20) and the variability commonly associated with environmental data, a limited number of trends were observed. Our most positive finding was improving trends for E. coli at 13 sites across four HUs. Although one or more sites in all HUs exceeded the E. coli WQO, there were nearly twice as many improving trends compared with worsening trends. Efforts to reduce contamination by communities, cities and counties by providing dog waste bags, porta-potties for homeless, source tracking and targeted sewer maintenance, may have lead to these improvements. The RCD in San Mateo County and their partners conducted directed efforts for restoration, sediment control and water management on San Gregorio and Pescadero Creeks where improving E coli trends were observed at 202-LAHON-11, 202-SANGR-12 and 202- PESCA- 11. Their Water for Farms, Fish and People project helped decrease diversion and increase flow in Pescadero Creek, which may have resulted in lower E coli levels (SMRCD 2016A). Restoration projects on both streams included sediment control and habitat structures for Steelhead, resulting in lower sediment transport that most likely helped reduce E coli as they attach to sediment (SMRCD 2016B, SMRCD 2017. Wu et al. 2019).

Water quality changes from efforts to manage nutrients are not yet evident. Landscapes with high agricultural or heavy urban influence show a high percent of years where the WQO is exceeded for

January 2020 38

Snapshot Day 20 Year Report nitrate and/or orthophosphate, and few trends were found for nutrients. Both improving and worsening trends were observed in nearly equal proportions. Five sites with worsening nitrate trends were in the Gabilan Watershed in Salinas Valley on three waterbodies: Natividad Creek, Alisal Creek and Tembladero Slough. Harkins Slough at Pajaro Valley Water Management’s pumping station (305- HARKI-22) showed an improving trend for both nitrate and orthophosphate. Although there have been extensive efforts to address agricultural pollution and stormwater runoff by growers, conservation professionals, and regulators, the effectiveness of these efforts and the results from implementing beneficial management practice (BMP) may not yet be observable by our trend analysis. A lag time between installation and a measured benefit from BMPs is common due to both physical and social reasons (Meals et al. 2010).

Obtaining good data that are accurate, complete and reliable using volunteers is a challenge faced by all citizen science programs (Galloway et al. 2006, Cohn 2008). The many problems and errors that are likely to be made more frequently by volunteers than professional staff include incorrect use of equipment, contamination of samples, incorrect site location, mislabeling of samples, incorrect recording of data, damage to equipment, and improper sample handling (eg. failure to chill samples). The Network has addressed these potential errors and mishaps through a number of measures including training, team composition, maps and photos of site locations, detailed field instructions that follow QAPP protocols, and careful data scrutiny. Training volunteers how to use scientific equipment allows volunteer monitoring efforts to increase the precision of the data collected, leading to meaningful information that can be used to detect changes and support conclusions (Cohn 2008). Careful data scrutiny for errors and omissions and the removal of spurious data is important when using volunteers (Cohn 2008, Dickenson et al. 2010). MBNMS and CWC staff review data sheets with teams to insure completeness and occasionally remove outliers outside of the feasible range for the water quality. Following a rigorous QAPP requires following sample handling procedures, lab standards and the calibration of equipment prior to each sampling event. Through oversight, training and management, the Network has addressed common concerns associated with the use of volunteers such that we believe our data are as reliable as those collected by technicians for CCAMP.

Team formation is critical to good data collection, so that volunteers are not overwhelmed by complex protocols and too much new information (Cohn 2008, Dickinson et al. 2010). Team formation pairs new volunteers with experienced volunteers, professionals with students, surfers with scientists, activists with government staff. Careful assignment of at least one person with prior monitoring experience to a team insures teams have the skill and confidence to properly collect samples and use field equipment. Sharing of common interests, direct involvement and the educational components of the program form the basis of a grass roots stakeholder building process in water quality and the land based influence of human activity on ocean health in the sanctuary. Undoubtedly the help of many volunteers, approximately 170 annually, makes a monitoring program such as Snapshot Day achieveable. The cost of these volunteers if they were paid would be over $18,000 annually, which could not be afforded by MBNMS or other contributing organizations.

Another common issue of citizen monitoring is the linkage and barriers to making collected data available and usable by decision-makers who can influence positive environmental change (Conrad & Hilchey 2010, Dickinson et al. 2010). MBNMS is fulfilling the formatting and data evaluation protocols needed to enter the data into a statewide data base. The data collected during Snapshot Day has been

January 2020 39

Snapshot Day 20 Year Report entered into the California Environmental Data Exchange Network (CEDEN) database through the Regional Data Center at Moss Landing Marine Labs. This data base provides access to data at a greater temporal and spatial frequency than what could be collected by a single organization. Central coast regulators have included Snapshot Day data in their review of regional water quality and decision- making process regarding listing 303(d) water bodies (personal communication, Karen Worcester 2013).

Program success can be measured by whether information collected brings about actions or policies that benefit the environment for the public good (Sullivan et al. 2009, Conrad and Hilchey 2010, Dickinson et al. 2010). Although environmental benefit has not yet been proven, a project to reduce pollutants and restore Santa Rita Creek was initiated. MBNMS staff observed that Santa Rita Creek, a small waterbody in north Salinas, was consistently identified as an Area of Concern and had consistent high nitrate concentrations at monitoring sites (as high as nitrate-N of 315 mg/L). As a result of this finding, a Prop 84 IRWM Implementation grant project was awarded for a collaborative effort between the Resource Conservation District of Monterey County (RCDMC), the Central Coast Wetlands Group (CCWG), and MBNMS staff to work with growers and neighbors to create awareness of watershed health, reduce nitrate contamination and restore habitat along the Ferrasci baseball field section of Santa Rita Creek. Similarly, in a separate effort under the leadership of the Coastal Watershed Council, the San Lorenzo River Alliance was formed in 2013 with objectives centered on water quality improvement, habitat restoration, public safety, community engagement and recreational enhancement.

5. CONCLUSION

One measure of Snapshot Day success is the continued ability to recruit a large number of volunteers to help with the environmental monitoring program across ten watersheds that enter the MBNMS over a time span of twenty years. Citizen involvement and the collaboration of Network organizations enables monitoring a greater geographic range and a higher density of sites than would be possible otherwise. Snapshot Day has also demonstrated that trained citizen scientists can effectively collect reliable and representative water quality data that can be analyzed and utilized by a variety of organizations for regional decision making. The data collected on Snapshot Day in combination with other regional monitoring data have been used by the CCAMP in assessing waterbody health and making 303(d) listing recommendations for impaired waters under the Clean Water Act. A collaborative regional project to restore Santa Rita Creek in Salinas was developed as a result of Snapshot Day observations. Thus Snapshot Day is directly linked to conservation activities and improved environmental management, a key determinant of successful citizen science programs (Conrad 2010)

Through their involvement, volunteers make a contribution to science and the health of Monterey Bay National Marine Sanctuary. Some volunteers join other MBNMS citizen science efforts including additional Network monitoring programs or local conservation efforts led by other groups. Yet the full potential of volunteer contribution may not be realized by the current program. Involving citizen scientists beyond monitoring tasks and engaging them in social processes aimed at community based initiatives, collaboration regarding sustainable resource management, and participation in local conservation planning may create broader community engagement toward effective ecosystem

January 2020 40

Snapshot Day 20 Year Report stewardship (Day & Litke 2005, Conrad & Daoust 2008, Divictor et al. 2010). Although the major focus is on the recruiting and education of volunteers, Network organizations have also advanced the program to the extent of inviting volunteers to define program objectives or engage in participatory conservation planning. For example, the Santa Rita Creek project and efforts by CWC along the San Lorenzo River are both examples of how citizen involvement has directed projects by Network organizations. This role extension is possible if volunteers are determined to make a difference and take a leadership role in their community or contribute to activities of other conservation related organizations.

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APPENDICES

January 2020 45

Appendix 1.A SSD Twenty Year Report: 2000-2019 WQO Exceedances for Lab Measured Analytes

Sites Monitored at Least 5 Years Nitrate as N Orthophosphate as P Ecoli Percent Percent Max # Years Years Max # Years Percent Years Max # Years Years # Years Concentration Exceeded Exceeded # Years Concentration Exceeded Exceeded # Years Concentration Exceeded Exceeded Site Code Site Name Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO 202-ALPIN-11 Alpine Creek at Alpine Road 17 0.77 0 0 16 0.36 8 50 16 3654 3 19 202-BEARG-11 Bear Gulch Creek at south fork confluence near Bear Creek8 Bridge 0.13 0 0 8 0.05 0 0 8 272 1 13 202-BUTAN-11 Butano Creek at Pescadero Road 16 4.31 2 13 15 0.1 0 0 16 228 0 0 202-CALER-11 Calera Creek at Reina del Mar 17 1.7 1 6 16 0.16 1 6 15 1106 4 27 202-CALER-12 Calera Creek near mouth 15 5.3 5 33 14 1.59 6 43 14 3654 5 36 202-DEERC-12 Deer Creek behind Creekside Smokehouse 9 0.77 0 0 9 0.05 0 0 9 24196 7 78 202-DENNI-11 Denniston Creek at HMB airport 16 2.49 3 19 14 0.1 0 0 15 754 4 27 202-FRENC-11 Frenchmans Creek at Venice Beach 16 4.07 7 44 15 0.11 0 0 15 712 5 33 202-GAZOS-11 Gazos Creek mouth 18 0.55 0 0 17 0.1 0 0 16 323 3 19 202-GAZOS-13 Gazos Creek at South Fork confluence 7 0.55 0 0 7 0.1 0 0 5 10 0 0 202-GAZOS-15 Gazos Creek at Old Woman's Creek Road 11 1.22 1 9 10 0.05 0 0 11 63 0 0 202-LAHON-11 San Gregorio Creek at La Honda 18 0.83 0 0 17 0.2 2 12 16 4717 7 44 202-LOBIT-11 Lobitas Creek on Lobitos Creek Road 18 1.54 1 6 18 0.18 2 11 15 7270 6 40 202-MARTI-11 Martini Creek in Montara State Beach at McNee Ranch19 1 1 5 18 0.1 0 0 18 657 1 6 202-MILLC-11 Mill Creek in Burliegh-Murray State Park 16 1.78 1 6 15 0.19 2 13 14 480 1 7 202-MONTA-11 Montara Creek upstream at Date and Harte Streets 16 0.93 0 0 15 0.1 0 0 15 4106 6 40 202-MONTA-12 Montara Creek downstream at Date and Harte Streets 18 0.92 0 0 18 0.1 0 0 17 24196 5 29 202-PESCA-11 Pescadero Creek at Stage Road Bridge adjacent to Community18 Church 0.57 0 0 17 0.18 1 6 17 886 3 18 202-PILAR-11 Pilarcitos Creek at Pilarcitos and Oak Avenues 17 4.88 10 59 15 0.14 1 7 15 1236 6 40 202-POMPO-11 Pomponio Creek mouth 18 1.2 1 6 17 0.21 2 12 16 19862 5 31 202-PURIS-11 Purisma Creek at Verde Road 16 0.39 0 0 16 0.21 3 19 16 680.5 5 31 202-SANGR-11 San Gregorio Creek State Beach 16 0.71 0 0 15 0.18 1 7 14 4106 4 29 202-SANGR-12 San Gregorio Creek at Stage Road 11 8.46 1 9 10 0.23 2 20 10 3255 4 40 202-SANGR-14 La Honda Creek 15 12.64 1 7 14 0.16 1 7 15 473 1 7 202-SANPE-11 San Pedro Creek at Oddstead 14 2.33 2 14 13 0.1 0 0 13 933 5 38 202-SANPE-12 San Pedro Creek north fork 16 0.82 0 0 15 0.1 0 0 15 350 3 20 202-SANPE-13 San Pedro Creek mouth 13 2.23 2 15 12 0.1 0 0 12 789 6 50 202-SANVI-11 San Vicente Creek at Cypress Avenue 18 1.83 2 11 17 0.1 0 0 18 24196 13 72 202-TUNIT-11 Tunitas Creek on Tunitas Creek Road 17 1 0 0 17 0.14 1 6 16 127.5 0 0 202-WHITE-11 Whitehouse Creek east 7 0.56 0 0 7 0.1 0 0 6 98 0 0 202-WHITE-12 Whitehouse Creek mouth 15 0.55 0 0 15 0.17 1 7 14 450 1 7 304-APTOS-21 Aptos Creek Nisene Marks State Park 14 0.5 0 0 14 0.18 2 14 12 168 0 0 304-APTOS-22 Aptos Creek near Aptos Valencia confluence 12 0.5 0 0 13 0.17 4 31 11 763 1 9 304-APTOS-23 Aptos Creek mouth 18 0.35 0 0 18 0.19 6 33 17 19863 11 65 304-ARANA-21 Arana Creek at Harbor High fish ladder 19 0.6 0 0 19 0.21 8 42 19 1320 12 63 304-ARANA-22 Arana Creek at north harbor 18 0.8 0 0 17 0.8 5 29 18 1274 6 33 304-ARANA-23 Arana Creek at Paul Sweet Road and Maybe Lane 12 0.56 0 0 12 0.27 7 58 12 1854 4 33 304-ARROY-21 Arroyo Creek at Meder Park 18 0.72 0 0 18 0.05 0 0 18 631 4 22 304-ARROY-22 Arroyo Creek at Delaware Ave 18 2.25 8 44 18 0.26 4 22 17 1768 7 41 304-ARROY-23 Arroyo Creek at West Cliff Drive 18 3.81 17 94 17 0.18 1 6 17 6131 5 29 304-BRANC-21 Branciforte Creek above confluence with San Lorenzo River17 0.5 0 0 18 0.19 2 11 17 1973 16 94 304-BRANC-22 Branciforte at DeLaveaga Park 13 0.53 0 0 13 0.2 3 23 11 2046 6 55 304-BRANC-23 Branciforte Creek at 434 Market Street 15 0.72 0 0 15 0.15 2 13 13 1866 10 77 304-BRANC-24 Branciforte Creek at Happy Valley School 9 0.4 0 0 9 0.14 1 11 9 833 4 44 304-BRANC-25 Branciforte Creek at 4055 Branciforte Drive 10 0.4 0 0 10 0.23 2 20 10 1014 2 20 304-CARBO-21 Carbonera Creek (trib to Branciforte Creek, Trib to San Lorenzo)18 0.96 0 0 18 0.21 1 6 17 1421 8 47 304-CORCO-21 Corcoran Lagoon at small bridge on East Cliff Drive 12 1.45 1 8 12 0.1 0 0 12 15531 3 25 304-CORCO-22 Corcoran Lagoon at Live Oak Library 12 0.88 0 0 12 0.05 0 0 12 24192 6 50 304-FERRA-21 Ferrari Creek at Cement Plant Road 14 0.14 0 0 14 0.11 0 0 12 24192 11 92 304-GRANI-21 Granite Creek on Granite Creek Road near Old Up Yonder8 Road 0.52 0 0 8 0.12 0 0 8 385 3 38 Appendix 1.A SSD Twenty Year Report: 2000-2019 WQO Exceedances for Lab Measured Analytes

Percent Percent Max # Years Years Max # Years Percent Years Max # Years Years # Years Concentration Exceeded Exceeded # Years Concentration Exceeded Exceeded # Years Concentration Exceeded Exceeded Site Code Site Name Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO 304-LAGUN-21 Laguna Creek On Laguna Road 14 0.3 0 0 12 0.05 0 0 12 976 1 8 304-LEONA-21 Leona Creek between Salerno and Pompeii Roads 6 0.8 0 0 6 0.08 0 0 8 1989 2 25 304-LIDEL-21 Lidell Creek on Bonny Doon Road 20 1.34 3 15 20 1.34 12 60 18 479 4 22 304-LITTL-21 Little Creek above confluence with Scott Creek 13 0.19 0 0 13 0.15 1 8 12 100 0 0 304-MAJOR-21 Majors Creek at Scaroni Road 13 0.33 0 0 13 0.21 1 8 11 988 3 27 304-MOLIN-21 Molino Creek at Swanton Road 14 1.07 1 7 14 0.28 5 36 12 571 2 17 304-MOORE-21 Moore Creek at the outflow of Antonelli Pond 16 0.5 0 0 16 0.05 0 0 15 121 0 0 304-MOORE-22 Moore Creek at UCSC grounds below Arboretum building11 closest to Empire0.54 Grade Road 0 0 11 0.05 0 0 10 100 0 0 304-MOORE-23 Moore Creek at Meder Street crossing (518 Meder Street)7 0.53 0 0 7 0.05 0 0 6 4352 3 50 304-MOORE-24 Moore Creek above Antonelli Pond 17 0.18 0 0 17 0.14 1 6 16 5172 11 69 304-MOORE-25 Moore Creek at UCSC grounds 13 0.32 0 0 13 0.05 0 0 12 548 4 33 304-MOORE-26 Moore Creek at mouth 17 0.2 0 0 17 0.2 1 6 17 3051 6 35 304-NEWYE-11 Ano Nuevo Creek mouth 15 1.31 1 7 15 0.09 0 0 15 857 1 7 304-PILKI-21 Pilkington Creek at Forbes Road 8 0.54 0 0 8 0.1 0 0 8 12976 8 100 304-PILKI-22 Pilkington Creek at Murray Road 8 0.9 0 0 8 0.27 2 25 8 8803 7 88 304-ROBSC-21 Rob's Creek along 34th Avenue 10 2.21 3 30 10 0.12 1 10 11 24196 9 82 304-SANLO-21 San Lorenzo River downtown 18 0.8 0 0 19 0.18 1 5 17 2143 10 59 304-SANLO-22 San Lorenzo River mouth 18 0.4 0 0 19 0.11 0 0 18 1553 6 33 304-SANLO-26 San Lorenzo River at the Garden of Eden 17 0.61 0 0 17 0.12 0 0 17 733 2 12 304-SANLO-27 San Lorenzo River at Junction Park 15 0.4 0 0 15 0.05 0 0 15 419 4 27 304-SANVI-21 San Vicente Creek on San Vicente Street in Davenport 14 0.3 0 0 13 0.05 0 0 12 100 0 0 304-SCOTT-21 Scott Creek upper 10 0.16 0 0 10 0.05 0 0 9 120 0 0 304-SCOTT-22 Scott Creek mid 19 0.5 0 0 19 0.29 1 5 18 216 0 0 304-SCOTT-23 Scott Creek lower 13 0.51 0 0 13 0.05 0 0 12 402 2 17 304-SCOTT-24 Scott Creek at Archibald Creek Park 13 0.43 0 0 13 0.16 1 8 12 100 0 0 304-SCOTT-25 Scott Creek at Hwy 1 14 0.5 0 0 14 0.12 0 0 14 100 0 0 304-SCSD-02 Santa Cruz storm drain on Merced Avenue at West Cliff12 Drive 4.42 12 100 12 0.14 1 8 12 7230 11 92 304-SCSD-03 Santa Cruz storm drain on Bay Street at Escalona 11 2.44 11 100 11 0.05 0 0 11 471 2 18 304-SCSD-04 Santa Cruz storm drain on Woodrow Ave at West Cliff Drive14 4.25 14 100 14 0.12 1 7 14 10462 8 57 304-SOQUE-21 Soquel Creek at Nob Hill 12 0.5 0 0 12 0.05 0 0 10 473 3 30 304-SOQUE-22 Soquel Creek at mouth 15 0.35 0 0 15 0.15 1 7 15 7270 8 53 304-VALEN-21 Valencia Creek at culvert off Valencia Creek Road 14 0.5 0 0 14 0.24 7 50 10 524 1 10 304-VALEN-22 Valencia Creeka at Aptos Creek confluence 13 0.8 0 0 14 0.2 6 43 11 1291 8 73 304-WADDE-21 Waddell Creek lower 18 0.29 0 0 18 0.13 1 6 16 100 0 0 304-WADDE-22 Waddell Creek upper 13 0.32 0 0 13 0.12 0 0 13 100 0 0 304-WILDE-21 Wilder Creek in State Park by building over creek 13 0.36 0 0 13 0.05 0 0 12 187 0 0 304-WILDE-22 Wilder Creek above the marsh at mouth 12 0.36 0 0 12 0.05 0 0 12 1187 3 25 304-ZAYAN-21 Zayante Creek 16 0.78 0 0 16 0.2 6 38 16 548 3 19 304-ZAYAN-22 Zayante Creek at Quail Hollow Road bridge 15 0.49 0 0 15 0.11 0 0 14 406.5 2 14 305-BEACH-21 Beach Road Ditch at Palm Beach 16 60.1 15 94 16 1.29 3 19 16 979 4 25 305-CORRA-21 Corralitos Creek at Thicket Lane and Green Valley Road16 8.71 4 25 5 0.08 0 0 16 3873 6 38 305-CORRA-22 Corralitos Creek at Eureka Canyon and Las Colinas Roads16 0.22 0 0 5 0.2 1 20 16 4106 4 25 305-HARKI-21 Harkins Slough at Harkins Slough Road MBNMS 17 0.8 0 0 17 0.69 3 18 17 5172 9 53 305-HARKI-22 Harkins Slough at Pajaro Valley Water Management Association15 Pump 11.83Station 7 47 15 0.38 8 53 15 8103 4 27 305-HARKI-23 Harkins Slough at Buena Vista Drive 17 2.4 3 18 17 0.31 2 12 17 3255 11 65 305-PAJAR-21 Pajaro River under Thurwachter Bridge 19 12 14 74 5 0.2 1 20 18 1145 4 22 305-STRUV-21 Struve Slough at Harkins Slough Road 17 1 0 0 5 0.5 4 80 18 645 5 28 305-STRUV-22 Struve Slough at Lee Road MBNMS 16 0.6 0 0 17 488 1 6 305-WATSO-21 Watsonville Slough at Harkins Slough Road 16 0.6 0 0 16 9208 3 19 305-WATSO-22 Watsonville Slough at Pajaro Valley Water Management16 Agency Pump18.44 Station 11 69 16 24196 4 25 Appendix 1.A SSD Twenty Year Report: 2000-2019 WQO Exceedances for Lab Measured Analytes

Percent Percent Max # Years Years Max # Years Percent Years Max # Years Years # Years Concentration Exceeded Exceeded # Years Concentration Exceeded Exceeded # Years Concentration Exceeded Exceeded Site Code Site Name Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO 305-WATSO-23 Watsonville Slough at Palm Beach Road 17 46.6 14 82 17 816 5 29 305-WSTRU-21 West Branch of Struve Slough at Harkins Slough Road and10 Green Valley1.01 Road junction (DFG0 Site) 0 12 2909 3 25 306-ELKHO-31 Elkhorn Slough at Kirby Park MBNMS 10 1.12 1 10 12 0.22 2 17 11 1414 2 18 306-ELKHO-32 Elkhorn Slough at Hudson's Landing 17 16.2 6 35 17 0.18 2 12 17 2420 6 35 306-ELKHO-33 Elkhorn Slough at South Marsh Bridge 15 1.1 1 7 15 0.1 0 0 15 2143 3 20 306-ELKHO-34 Elkhorn Slough at Garin Road 18 48.2 15 83 18 4.26 10 56 18 1860 10 56 306-MOROC-31 Moro Cojo Slough upper 18 37 15 83 6 2.4 4 67 17 5040 15 88 306-MOROC-32 Moro Cojo Slough at Castroville Slough Confluence 12 6.66 4 33 12 1000 6 50 306-MOROC-33 Moro Cojo Slough lower 19 5.18 2 11 6 0.1 0 0 19 1986 2 11 306-MOROC-34 Castroville Slough above the confluence with the Moro Cojo6 Slough 8.7 1 17 6 0.4 3 50 7 1829 4 57 307-CARME-33 Carmel River at Rosie's Bridge 19 0.1 0 0 19 0.1 0 0 18 218 0 0 307-CARME-35 Carmel River at Garland Park 19 0.2 0 0 19 0.1 0 0 16 293 1 6 307-CARME-36 Carmel River at Schulte Road MBNMS 19 0.1 0 0 19 0.1 0 0 18 216 0 0 307-CARME-37 Carmel River at Hacienda Carmel 15 0.1 0 0 16 0.1 0 0 15 216 0 0 307-CARME-38 Carmel River at Hwy 1 MBNMS 18 0.95 0 0 18 0.1 0 0 17 471 1 6 307-CARME-39 Carmel River mouth 12 0.66 0 0 12 0.13 1 8 11 1050 5 45 307-GARZA-31 Garzas Creek at Garzas Road 14 0.1 0 0 14 0.1 0 0 13 135 0 0 307-HATTO-31 Hatton Canyon at Carmel Valley Road 8 0.3 0 0 8 0.33 4 50 8 1274 1 13 308-BIGCR-31 Big Creek at Hwy 1 MBNMS 10 0.06 0 0 11 0.05 0 0 10 100 0 0 308-BIGSU-31 Big Sur River at Andrew Molera Park 19 0.36 0 0 19 0.1 0 0 18 200 0 0 308-BIGSU-32 Big Sur River near Whaling Bridge at Julia Pfifer State Park12 0.1 0 0 13 0.1 0 0 13 856 1 8 308-DANIC-31 Dani Creek at Hwy 1 8 0.4 0 0 8 0.05 0 0 9 100 0 0 308-DOUD-31 Doud Creek at trail crossing 16 0.62 0 0 16 0.1 0 0 15 2011 2 13 308-GARRA-31 Garrapata Creek 17 0.71 0 0 17 0.1 0 0 17 245 1 6 308-HOTSP-31 Hot Springs Creek at Esalen 19 0.88 0 0 18 0.1 0 0 18 979 1 6 308-LIMEK-31 Limekiln Creek at Hwy 1 15 0.3 0 0 15 0.14 1 7 16 432 1 6 308-MALPA-31 Malpaso Creek 17 1.09 1 6 17 0.1 0 0 17 115.5 0 0 308-MCWAY-31 McWay Canyon in camground upstream of Hwy 1 18 0.3 0 0 18 0.19 1 6 17 100 0 0 308-MILLC-31 Mill Creek at Hwy 1 10 0.3 0 0 11 0.05 0 0 11 100 0 0 308-PALOC-31 Palo Colorado Canyon at first driveway to right 20 0.28 0 0 20 0.16 1 5 19 618 7 37 308-PARTI-31 Partington Canyon at Tan Bark Trail 13 0.3 0 0 12 0.1 0 0 12 100 0 0 308-PLASK-31 Plaskett Creek at Hwy 1 12 0.05 0 0 12 0.05 0 0 13 153 0 0 308-PREWI-31 Prewitt Creek at Hwy 1 10 0.05 0 0 10 0.05 0 0 11 100 0 0 308-ROCKY-31 Rocky Creek (Private property) 16 0.3 0 0 16 0.16 1 6 16 327 1 6 308-SANJO-31 San Jose Creek at Hwy 1 18 0.2 0 0 18 0.16 1 6 17 487 2 12 308-SOBER-31 Soberanes Creek Bridge Trail 17 0.67 0 0 17 0.1 0 0 16 100 0 0 308-SYCAM-31 Sycamore Canyon upper 16 0.3 0 0 16 0.1 0 0 16 100 0 0 308-SYCAM-32 Sycamore Canyon lower 6 0.1 0 0 6 0.1 0 0 6 89 0 0 308-VICEN-31 Vicente Creek at Hwy 1 10 0.07 0 0 10 0.05 0 0 11 100 0 0 308-WILDC-31 Wild Cattle Creek at Hwy 1 10 0.08 0 0 11 0.36 1 9 11 100 0 0 308-WILLO-31 Willow Creek mouth 10 0.05 0 0 10 0.05 0 0 11 100 0 0 309-ALISA-32 Alisal Creek upper 20 52.9 19 95 20 1.68 20 100 19 28500 16 84 309-ASILO-31 Asilomar State Park at bridge 19 1.22 2 11 19 0.18 1 5 19 2380 8 42 309-ATASC-41 Atascadero Creek at West Mall Bridge 16 0.3 0 0 16 0.15 1 6 15 2846.33 9 60 309-ATASC-42 Atascadero Creek at Three Bridges on Morro Road 15 0.1 0 0 15 0.34 1 7 14 486 5 36 309-CENTR-31 Greenwood Park at Central and 13th Streets in Pacific Grove18 5.77 16 89 18 0.46 4 22 17 48392 17 100 309-DOLPH-31 Dolphin Brook at end of Van Buren Street 9 1.38 3 33 9 0.18 2 22 9 3870 4 44 309-GABIL-31 Gabilan Creek at Independence Road 14 30.7 14 100 14 0.6 7 50 14 1483 7 50 309-GRAVE-41 Graves Creek at Monterey Road 13 0.3 0 0 13 0.1 0 0 13 4352 8 62 309-LIBRA-31 Library or Hartnell Gulch behind Monterey City library 18 0.7 0 0 18 0.1 0 0 17 2691 16 94 Appendix 1.A SSD Twenty Year Report: 2000-2019 WQO Exceedances for Lab Measured Analytes

Percent Percent Max # Years Years Max # Years Percent Years Max # Years Years # Years Concentration Exceeded Exceeded # Years Concentration Exceeded Exceeded # Years Concentration Exceeded Exceeded Site Code Site Name Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO Sampled (mg/L) WQO WQO 309-MAJOR-31 Majors Creek lower 18 0.23 0 0 18 0.1 0 0 17 2100 7 41 309-NATIV-31 Natividad Creek at Las Casitas Road 17 48.1 14 82 17 1 14 82 16 4500 13 81 309-PASOR-41 Paso Robles Creek at Santa Rita Road 13 0.79 0 0 13 0.06 0 0 11 1095.67 2 18 309-RECDI-31 Reclamation Ditch at Davis Road 18 39.8 18 100 18 0.94 15 83 17 41058 15 88 309-RINCO-41 Rinconada Pozo Road 12 0.4 0 0 12 0.1 0 0 11 7270 8 73 309-SALIN-31 Salinas River at Gypse Camp 19 40.05 19 100 19 0.27 10 53 19 427 3 16 309-SALIN-32 Salinas River at Davis Road MBNMS 18 23.9 15 83 18 0.28 6 33 18 38998.5 3 17 309-SALIN-33 Salinas River at Chualar Bridge 16 6.2 7 44 16 0.1 2 13 16 521 1 6 309-SALIN-44 Salinas River at Curbaril Bridge 14 0.6 0 0 14 0.1 1 7 13 1465.33 4 31 309-SALIN-45 Salinas River at Old Hwy 58 Bridge 17 0.89 0 0 17 1.38 1 6 18 999.5 1 6 309-SALIN-46 Salinas River San Miguel at Estralia Rock 12 2.14 0 0 12 0.47 10 83 9 3609 3 33 309-SALIN-47 Salinas River at 13th Street bridge in Paso Robles 14 1.3 0 0 14 0.23 5 36 11 1008.33 1 9 309-SKYLI-31 Skyline at Forest Knoll Road 9 0.54 0 0 9 0.27 2 22 8 2028 4 50 309-SMARG-41 Santa Margarita Creek at El Camino Real and Asuncion Road16 0.4 0 0 16 0.1 0 0 15 3255 10 67 309-SRITA-32 Santa Rita Creek at Bellizona 10 15.1 6 60 10 61314 10 100 309-SRITA-33 Santa Rita Creek at the 14th hole Salinas Valley Golf Course6 14.4 3 50 6 13734 6 100 309-SRITA-34 Santa Rita Creek at Russell Road 12 54 6 50 5 0.4 5 100 12 98039 12 100 309-SRITA-35 Santa Rita Creek at Van Buren Avenue 12 314 7 58 5 1.4 3 60 12 220293 12 100 309-TEMBL-31 Tembladero Slough at Monterey Dunes 19 60.5 16 84 6 0.45 4 67 19 39895 12 63 309-TEMBL-32 Tembladero Slough Hwy 183 19 53.5 16 84 6 0.4 2 33 18 8859 10 56 309-TEMBL-33 Tembladero Slough at Preston Bridge 16 74.7 15 94 6 0.5 5 83 15 26838 13 87 309-TROUT-41 Trout Creek at 3 bridges 18 0.8 0 0 18 0.41 14 78 15 1374 14 93 309-UPPER-31 Natividad Creek upper 16 68.3 13 81 16 1.07 13 81 15 18501 15 100 309-VETER-31 Veteran's Park at big turn in Veterans Drive 15 0.4 0 0 15 0.27 1 7 14 520 3 21 309-YERBA-41 Yerba Buena Creek at Estrada and Hwy 58 9 0.1 0 0 9 0.33 6 67 10 1671.33 9 90 310-ARROY-41 Arroyo del Puerto at bridge in San Simeon 13 0.1 0 0 13 0.1 0 0 13 8789.33 7 54 310-ARROY-42 Arroyo de la Cruz under Hwy 1 13 0.2 0 0 13 0.1 0 0 12 1725 4 33 310-CARPO-41 San Carpoforo Creek upstream of mouth 14 0.1 0 0 14 0.1 0 0 14 180.33 0 0 310-DAL-41 Dairy Creek lower at Dairy Creek Road 5 0.1 0 0 6 0.06 0 0 5 1210 2 40 310-LAGUN-41 Arroyo Laguna mouth 11 0.06 0 0 11 0.05 0 0 11 9208 10 91 310-LITTL-41 Little Pico Creek at Hwy 1 7 0.05 0 0 7 0.04 0 0 7 833 3 43 310-PENN-41 Pennington Creek 9 0.2 0 0 8 0.07 0 0 9 906 7 78 310-PICOC-41 Pico Creek under Hwy 1 Bridge 11 0.1 0 0 11 0.1 0 0 11 942.33 3 27 310-SANSI-41 San Simeon Creek at campground bridge 17 13 10 59 17 1 8 47 16 1050.33 7 44 310-SANSI-42 San Simeon Creek at Red Mountain Road 5 0.05 0 0 5 0.05 0 0 6 645 3 50 310-SANTA-41 Santa Rosa Creek at Hwy 1 MBNMS 16 0.4 0 0 17 0.1 0 0 15 1401 6 40 310-SANTA-42 Santa Rosa Creek at Ferrasci Road 14 0.5 0 0 14 0.1 0 0 15 1664 3 20 310-SANTA-43 Santa Rosa Creek at Windsor 9 0.4 0 0 10 0.1 0 0 11 556 3 27 310-SBE-41 San Bernardo Creek 7 0.7 0 0 7 0.15 5 71 5 24192 5 100 310-SYB-41 Santa Ysabela Creek on Turri Road 15 11 9 60 15 0.32 6 40 13 1485.33 2 15 310-UCF-41 Upper Chorro Flats at Chorro Creek and Morro Creek Roads15 3.8 11 73.33 15 0.59 12 80 13 1120 3 23 317-ESTRE-43 Estrella River at Whitley Gardens 8 1.26 1 13 8 0.08 0 0 8 11513.33 5 63 Appendix 1.B SSD Twenty Year Report: 2000-2019 WQO Exceedances for Field Measurements

Sites Monitored at Least 5 Years Dissolved Oxygen pH` Water Temperature Turbidity Transparency Maximum % Years % Years Max % Years % Years Maximum Minimum # Years Concentration Exceeded Maximum Exceeded Temperature % Years Exceeded Exceeded (NTU) (cm) Site Code Site Name Sampled (mg/L) WQO WQO (⁰C.) Exceeded WQO WQO WQO 202-ALPIN-11 Alpine Creek at Alpine Road 17 13.6 6 7.0 0 14.0 0 45.0 NM 115 0 202-BEARG-11 Bear Gulch Creek at south fork confluence near Bear Creek Bridge 8 9 13 7.0 25 13.1 0 NM 120 0 202-BUTAN-11 Butano Creek at Pescadero Road 15 11.2 20 8.0 0 13.7 0 10.0 NM 2 8 202-CALER-11 Calera Creek at Reina del Mar 17 10 29 7.7 6 14.0 0 15.0 NM 93 0 202-CALER-12 Calera Creek near mouth 16 10 19 7.6 0 19.4 0 5.0 NM 51 0 202-DEERC-12 Deer Creek behind Creekside Smokehouse 8 11 0 7.5 0 13.3 0 0.5 NM 42 0 202-DENNI-11 Denniston Creek at HMB airport 16 10.5 6 8.0 6 13.9 0 5.0 0 63 0 202-FRENC-11 Frenchmans Creek at Venice Beach 16 12 6 7.5 0 16.0 0 30.0 14 13 17 202-GAZOS-11 Gazos Creek mouth 16 11 19 7.5 6 18.0 0 5.0 NM 115 0 202-GAZOS-13 Gazos Creek at South Fork confluence 7 11 0 7.5 14 12.0 0 1.0 NM 120 0 202-GAZOS-15 Gazos Creek at Old Woman's Creek Road 11 11 18 7.5 9 13.2 0 4.5 NM 120 0 202-LAHON-11 San Gregorio Creek at La Honda 18 12.8 0 8.0 0 13.0 0 30.0 17 90 0 202-LOBIT-11 Lobitas Creek on Lobitos Creek Road 18 11.4 0 8.5 0 13.0 0 88.0 22 35 0 202-MARTI-11 Martini Creek in Montara State Beach at McNee Ranch 19 11 11 7.5 16 15.0 0 80.0 20 42 0 202-MILLC-11 Mill Creek in Burliegh-Murray State Park 15 11.8 0 7.5 0 13.9 0 17.6 0 81 0 202-MONTA-11 Montara Creek upstream at Date and Harte Streets 15 9.15 47 7.0 27 16.0 0 40.0 NM 1 40 202-MONTA-12 Montara Creek downstream at Date and Harte Streets 18 9.2 39 7.0 28 15.5 0 40.0 NM 1 38 202-PESCA-11 Pescadero Creek at Stage Road Bridge adjacent to Community Church 17 11.2 24 8.0 6 15.0 0 5.0 NM 85 0 202-PILAR-11 Pilarcitos Creek at Pilarcitos and Oak Avenues 16 11.5 6 7.5 0 14.2 0 37.5 14 61 0 202-POMPO-11 Pomponio Creek mouth 17 14.69 12 8.0 6 22.0 6 30.0 NM 35 0 202-PURIS-11 Purisma Creek at Verde Road 17 11.2 6 8.5 6 14.0 0 10.0 0 46 0 202-SANGR-11 San Gregorio Creek State Beach 16 12.61 6 8.5 0 19.5 0 85.0 11 44 0 202-SANGR-12 San Gregorio Creek at Stage Road 10 12.96 10 8.0 0 15.5 0 10.0 NM 120 0 202-SANGR-14 La Honda Creek 15 10.5 7 7.5 0 11.9 0 5.0 NM 65 0 202-SANPE-11 San Pedro Creek at Oddstead 14 11.4 0 7.9 0 16.9 0 10.0 0 97 0 202-SANPE-12 San Pedro Creek north fork 15 11 7 8.1 7 13.7 0 5.0 NM 117 0 202-SANPE-13 San Pedro Creek mouth 12 11 0 8.0 0 14.7 0 5.0 NM 100 0 202-SANVI-11 San Vicente Creek at Cypress Avenue 18 10 6 7.5 22 17.4 0 10.0 NM 28 0 202-TUNIT-11 Tunitas Creek on Tunitas Creek Road 17 11.1 0 8.5 6 12.7 0 5.0 0 46 0 202-WHITE-11 Whitehouse Creek east 6 10.8 0 7.5 0 13.0 0 20.0 0 114 0 202-WHITE-12 Whitehouse Creek mouth 13 10.5 8 7.5 7 14.3 0 30.0 40 38 0 304-APTOS-21 Aptos Creek Nisene Marks State Park 11 11 0 8.0 0 13.0 0 15.0 0 120 0 304-APTOS-22 Aptos Creek near Aptos Valencia confluence 11 11.2 9 8.3 0 13.4 0 10.0 0 120 0 304-APTOS-23 Aptos Creek mouth 16 12.61 13 8.0 0 16.9 0 20.0 0 48 0 304-ARANA-21 Arana Creek at Harbor High fish ladder 17 11.6 24 7.5 0 23.0 5 15.0 NM 21 8 304-ARANA-22 Arana Creek at north harbor 17 13.6 53 9.0 6 21.0 0 20.0 NM 13 9 304-ARANA-23 Arana Creek at Paul Sweet Road and Maybe Lane 11 14.1 18 8.5 9 13.4 0 5.0 NM 60 0 304-ARROY-21 Arroyo Creek at Meder Park 15 9.4 33 7.5 6 18.0 0 5.0 NM 35 0 304-ARROY-22 Arroyo Creek at Delaware Ave 16 12 25 8.0 6 20.2 0 15.0 0 43 0 304-ARROY-23 Arroyo Creek at West Cliff Drive 16 12.1 13 8.0 6 19.0 0 15.0 0 59 0 304-BRANC-21 #N/A 17 14.1 12 8.5 6 22.0 6 5.0 NM 20 15 304-BRANC-22 Branciforte at DeLaveaga Park 11 10 9 7.3 0 14.5 0 NM 25 0 304-BRANC-23 Branciforte Creek at 434 Market Street 13 11 8 7.5 7 15.0 0 NM 61 0 304-BRANC-24 Branciforte Creek at Happy Valley School 7 10 29 7.5 0 13.2 0 0.5 NM 10 25 304-BRANC-25 Branciforte Creek at 4055 Branciforte Drive 8 10.8 0 8.0 0 13.6 0 10.0 NM 10 20 304-CARBO-21 Carbonera Creek (trib to Branciforte Creek, Trib to San Lorenzo) 15 10.4 20 8.0 0 15.0 0 5.0 NM 61 0 304-CORCO-21 Corcoran Lagoon at small bridge on East Cliff Drive 12 10.92 0 9.5 31 24.0 23 25.0 0 29 0 304-CORCO-22 Corcoran Lagoon at Live Oak Library 13 10.32 46 8.7 8 21.9 8 30.0 40 42 0 304-FERRA-21 Ferrari Creek at Cement Plant Road 12 10 0 7.0 0 14.4 0 5.0 NM 115 0 304-GRANI-21 Granite Creek on Granite Creek Road near Old Up Yonder Road 7 10.6 14 7.5 0 13.1 0 5.0 NM 10 33 304-LAGUN-21 Laguna Creek On Laguna Road 13 12.6 0 7.5 0 17.5 0 2.5 NM 120 0 304-LEONA-21 Leona Creek between Salerno and Pompeii Roads 6 5 100 7.3 0 14.5 0 NM 29 0 304-LIDEL-21 Lidell Creek on Bonny Doon Road 18 10.5 17 7.5 11 14.6 0 10.0 NM 100 0 Appendix 1.B SSD Twenty Year Report: 2000-2019 WQO Exceedances for Field Measurements

Sites Monitored at Least 5 Years Dissolved Oxygen pH` Water Temperature Turbidity Transparency Maximum % Years % Years Max % Years % Years Maximum Minimum # Years Concentration Exceeded Maximum Exceeded Temperature % Years Exceeded Exceeded (NTU) (cm) Site Code Site Name Sampled (mg/L) WQO WQO (⁰C.) Exceeded WQO WQO WQO 304-LITTL-21 Little Creek above confluence with Scott Creek 10 11 10 7.0 0 14.5 0 0.0 NM 47 0 304-MAJOR-21 Majors Creek at Scaroni Road 12 12.5 8 7.5 8 14.0 0 20.0 NM 71 0 304-MOLIN-21 Molino Creek at Swanton Road 13 10.82 0 7.5 0 14.0 0 10.0 NM 109 0 304-MOORE-21 Moore Creek at the outflow of Antonelli Pond 17 10.4 59 7.7 12 20.7 0 10.0 NM 1 9 304-MOORE-22 Moore Creek at UCSC grounds below Arboretum building closest to Empire9 Grade Road8 89 7.0 0 14.1 0 10.0 NM 57 0 304-MOORE-23 Moore Creek at Meder Street crossing (518 Meder Street) 5 9.2 0 7.5 14 15.0 0 10.0 NM 44 0 304-MOORE-24 Moore Creek above Antonelli Pond 14 9.6 50 7.0 13 13.2 0 100.0 20 52 0 304-MOORE-25 Moore Creek at UCSC grounds 11 9.8 18 7.5 0 14.2 0 10.0 NM 60 0 304-MOORE-26 Moore Creek at mouth 16 11 19 8.5 18 27.7 41 40.0 NM 26 0 304-NEWYE-11 Ano Nuevo Creek mouth 14 10 14 7.5 15 15.0 0 25.0 NM 92 0 304-PILKI-21 Pilkington Creek at Forbes Road 8 7 88 7.5 25 14.7 0 NM 51 0 304-PILKI-22 Pilkington Creek at Murray Road 8 7 75 7.5 25 14.6 0 NM 44 0 304-ROBSC-21 Rob's Creek along 34th Avenue 10 14 70 8.3 10 21.5 10 5.0 NM 60 0 304-SANLO-21 San Lorenzo River downtown 18 10.5 11 8.3 0 17.1 0 10.0 NM 60 0 304-SANLO-22 San Lorenzo River mouth 18 11.6 11 8.0 0 19.9 0 5.0 NM 10 8 304-SANLO-26 San Lorenzo River at the Garden of Eden 16 13.3 6 7.5 0 20.2 0 6.3 0 100 0 304-SANLO-27 San Lorenzo River at Junction Park 14 12 7 8.0 7 16.6 0 4.5 0 120 0 304-SANVI-21 San Vicente Creek on San Vicente Street in Davenport 11 10 0 7.5 0 13.7 0 5.0 NM 120 0 304-SCOTT-21 Scott Creek upper 7 11 14 7.0 11 12.6 0 NM 47 0 304-SCOTT-22 Scott Creek mid 15 11 20 7.5 17 13.0 0 0.0 NM 46 0 304-SCOTT-23 Scott Creek lower 10 11 20 7.0 8 14.0 0 0.0 NM 47 0 304-SCOTT-24 Scott Creek at Archibald Creek Park 10 11 10 7.0 17 16.0 0 0.0 NM 47 0 304-SCOTT-25 Scott Creek at Hwy 1 13 10.2 15 7.3 23 14.5 0 NM 60 0 304-SCSD-02 Santa Cruz storm drain on Merced Avenue at West Cliff Drive 11 9 36 7.5 0 18.4 0 0.0 NM 60 0 304-SCSD-03 Santa Cruz storm drain on Bay Street at Escalona 10 10 10 8.0 0 17.5 0 5.0 NM 60 0 304-SCSD-04 Santa Cruz storm drain on Woodrow Ave at West Cliff Drive 13 12 15 8.0 0 20.4 0 5.0 NM 53 0 304-SOQUE-21 Soquel Creek at Nob Hill 8 11.6 13 7.5 0 14.5 0 30.0 NM 100 0 304-SOQUE-22 Soquel Creek at mouth 14 12.75 14 8.0 7 16.0 0 50.0 NM 50 0 304-VALEN-21 Valencia Creek at culvert off Valencia Creek Road 11 11 0 8.0 0 13.0 0 10.0 0 120 0 304-VALEN-22 Valencia Creeka at Aptos Creek confluence 10 10.85 10 8.0 0 14.4 0 50.0 14 61 0 304-WADDE-21 Waddell Creek lower 14 11 7 7.5 14 14.9 0 20.0 NM 120 0 304-WADDE-22 Waddell Creek upper 10 9.7 0 7.0 9 15.0 0 30.0 NM 120 0 304-WILDE-21 Wilder Creek in State Park by building over creek 12 11.4 8 8.4 0 14.5 0 2.5 NM 120 0 304-WILDE-22 Wilder Creek above the marsh at mouth 11 11.6 0 7.5 0 18.0 0 9.4 NM 120 0 304-ZAYAN-21 Zayante Creek 14 11.22 0 7.5 7 16.3 0 5.0 0 120 0 304-ZAYAN-22 Zayante Creek at Quail Hollow Road bridge 13 11.69 0 8.0 8 17.0 0 5.4 0 78 0 305-BEACH-21 Beach Road Ditch at Palm Beach 13 16.89 8 8.5 0 24.0 14 25.0 0 17 13 305-CORRA-21 Corralitos Creek at Thicket Lane and Green Valley Road 14 12 7 8.3 0 17.0 0 10.0 NM 110 0 305-CORRA-22 Corralitos Creek at Eureka Canyon and Las Colinas Roads 13 12 15 8.0 0 14.2 0 5.0 NM 120 0 305-HARKI-21 Harkins Slough at Harkins Slough Road MBNMS 15 13.54 40 7.9 0 23.0 50 200.0 60 7 86 305-HARKI-22 Harkins Slough at Pajaro Valley Water Management Association Pump 13Station 12 69 8.0 8 19.0 0 40.0 40 7 57 305-HARKI-23 Harkins Slough at Buena Vista Drive 15 10.16 40 8.2 0 15.8 0 25.0 NM 20 11 305-PAJAR-21 Pajaro River under Thurwachter Bridge 17 17.67 29 8.2 0 20.7 0 25.0 0 40 0 305-STRUV-21 Struve Slough at Harkins Slough Road 13 9.2 77 7.1 7 23.8 7 100.0 17 12 25 305-STRUV-22 Struve Slough at Lee Road MBNMS 13 8.6 77 7.5 0 24.0 36 5.1 0 7 33 305-WATSO-21 Watsonville Slough at Harkins Slough Road 12 7.2 83 7.5 0 20.0 0 12.7 0 59 0 305-WATSO-22 Watsonville Slough at Pajaro Valley Water Management Agency Pump 14Station 12.32 64 7.9 0 23.7 14 70.0 20 12 14 305-WATSO-23 Watsonville Slough at Palm Beach Road 13 12 23 8.5 0 24.0 14 150.0 40 15 38 305-WSTRU-21 West Branch of Struve Slough at Harkins Slough Road and Green Valley 9Road junction (DFG9.3 Site) 78 7.0 9 21.5 9 15.0 0 7 25 306-ELKHO-31 Elkhorn Slough at Kirby Park MBNMS 12 8 75 8.5 0 20.5 0 13.3 NM 22 10 306-ELKHO-32 Elkhorn Slough at Hudson's Landing 18 11 50 9.0 6 22.8 22 44.9 NM 15 53 306-ELKHO-33 Elkhorn Slough at South Marsh Bridge 16 11 56 8.5 0 22.0 6 18.1 NM 34 0 306-ELKHO-34 Elkhorn Slough at Garin Road 18 16.4 11 8.6 6 19.0 0 69.8 NM 34 0 Appendix 1.B SSD Twenty Year Report: 2000-2019 WQO Exceedances for Field Measurements

Sites Monitored at Least 5 Years Dissolved Oxygen pH` Water Temperature Turbidity Transparency Maximum % Years % Years Max % Years % Years Maximum Minimum # Years Concentration Exceeded Maximum Exceeded Temperature % Years Exceeded Exceeded (NTU) (cm) Site Code Site Name Sampled (mg/L) WQO WQO (⁰C.) Exceeded WQO WQO WQO 306-MOROC-31 Moro Cojo Slough upper 19 18.42 26 9.0 16 26.0 21 100.0 NM 1 88 306-MOROC-32 Moro Cojo Slough at Castroville Slough Confluence 12 15.5 42 9.5 85 26.6 75 90.0 NM 2 100 306-MOROC-33 Moro Cojo Slough lower 20 14.7 35 9.9 60 30.0 47 NM 4 84 306-MOROC-34 Castroville Slough above the confluence with the Moro Cojo Slough 6 11.2 0 9.0 17 19.9 0 NM 7 83 307-CARME-33 Carmel River at Rosie's Bridge 19 12 0 7.5 5 16.0 0 NM 100 0 307-CARME-35 Carmel River at Garland Park 19 12 5 7.5 5 16.8 0 NM 89 0 307-CARME-36 Carmel River at Schulte Road MBNMS 19 12.2 5 8.0 5 17.0 0 NM 65 0 307-CARME-37 Carmel River at Hacienda Carmel 17 11.2 0 8.0 6 17.9 0 NM 35 0 307-CARME-38 Carmel River at Hwy 1 MBNMS 17 10.7 6 8.0 6 18.0 0 NM 21 7 307-CARME-39 Carmel River mouth 13 9.8 23 7.5 8 18.7 0 NM 92 0 307-GARZA-31 Garzas Creek at Garzas Road 14 11 0 7.3 7 16.0 0 NM 20 8 307-HATTO-31 Hatton Canyon at Carmel Valley Road 8 9.5 38 8.0 0 15.1 0 NM 24 13 308-BIGCR-31 Big Creek at Hwy 1 MBNMS 12 11 0 8.3 0 15.4 0 5.0 NM 46 0 308-BIGSU-31 Big Sur River at Andrew Molera Park 17 12 6 8.0 6 16.2 0 NM 43 0 308-BIGSU-32 Big Sur River near Whaling Bridge at Julia Pfifer State Park 12 10.92 0 7.5 0 17.6 0 NM 67 0 308-DANIC-31 Dani Creek at Hwy 1 10 10.7 0 8.3 0 17.6 0 5.0 NM 117 0 308-DOUD-31 Doud Creek at trail crossing 16 12 6 7.8 0 13.2 0 NM 73 0 308-GARRA-31 Garrapata Creek 17 12 0 8.0 0 13.0 0 NM 29 0 308-HOTSP-31 Hot Springs Creek at Esalen 19 12 5 8.0 0 14.5 0 NM 100 0 308-LIMEK-31 Limekiln Creek at Hwy 1 16 11.71 0 8.3 6 15.9 0 5.0 NM 46 0 308-MALPA-31 Malpaso Creek 16 11.4 6 7.5 6 14.1 0 NM 22 7 308-MCWAY-31 McWay Canyon in camground upstream of Hwy 1 18 12 0 8.0 6 15.0 0 NM 100 0 308-MILLC-31 Mill Creek at Hwy 1 12 11 0 8.2 0 14.0 0 0.0 NM 46 0 308-PALOC-31 Palo Colorado Canyon at first driveway to right 20 11 0 8.3 0 13.4 0 NM 10 6 308-PARTI-31 Partington Canyon at Tan Bark Trail 13 12 8 7.5 0 15.0 0 NM 74 0 308-PLASK-31 Plaskett Creek at Hwy 1 14 11.1 0 8.3 7 13.7 0 0.0 NM 12 10 308-PREWI-31 Prewitt Creek at Hwy 1 12 10.7 0 8.1 0 13.5 0 0.0 NM 46 0 308-ROCKY-31 Rocky Creek (Private property) 16 11.5 0 7.5 0 12.5 0 NM 1 6 308-SANJO-31 San Jose Creek at Hwy 1 18 11 11 7.7 17 15.0 0 NM 15 6 308-SOBER-31 Soberanes Creek Bridge Trail 17 11 12 8.0 6 15.0 0 NM 112 0 308-SYCAM-31 Sycamore Canyon upper 15 10.21 47 7.5 0 15.0 0 NM 63 0 308-SYCAM-32 Sycamore Canyon lower 6 9 17 7.5 0 14.2 0 NM 120 0 308-VICEN-31 Vicente Creek at Hwy 1 12 11.1 0 8.3 8 13.7 0 5.0 NM 22 13 308-WILDC-31 Wild Cattle Creek at Hwy 1 12 11 0 8.3 8 12.6 0 5.0 NM 46 0 308-WILLO-31 Willow Creek mouth 12 11.5 0 8.6 8 14.5 0 0.0 NM 46 0 309-ALISA-32 #N/A 20 12 45 9.0 5 22.5 15 NM 2 95 309-ASILO-31 Asilomar State Park at bridge 19 9 53 7.5 0 18.0 0 15.0 NM 48 0 309-ATASC-41 Atascadero Creek at West Mall Bridge 16 10 31 8.5 6 17.0 0 5.0 NM 41 0 309-ATASC-42 Atascadero Creek at Three Bridges on Morro Road 15 11 20 9.0 13 15.7 0 0.0 NM 60 0 309-CENTR-31 #N/A 18 10 11 8.0 0 18.5 0 5.0 NM 53 0 309-DOLPH-31 Dolphin Brook at end of Van Buren Street 9 10 33 7.5 0 14.1 0 NM 37 0 309-GABIL-31 Gabilan Creek at Independence Road 14 10 7 7.6 0 20.3 0 NM 3 7 309-GRAVE-41 Graves Creek at Monterey Road 13 10 38 9.0 8 16.0 0 0.0 NM 60 0 309-LIBRA-31 Library or Hartnell Gulch behind Monterey City library 16 10 13 7.5 12 14.9 0 NM 8 6 309-MAJOR-31 Majors Creek lower 18 10.5 22 7.8 0 15.0 0 NM 41 0 309-PASOR-41 Paso Robles Creek at Santa Rita Road 12 9.05 25 8.5 0 17.0 0 5.0 0 1 9 309-RECDI-31 Reclamation Ditch at Davis Road 18 12.04 22 8.3 0 23.4 17 NM 3 82 309-RINCO-41 Rinconada Pozo Road 13 9.1 46 8.5 8 19.0 0 80.0 NM 60 0 309-SALIN-31 Salinas River at Gypse Camp 20 12 5 9.0 10 21.5 11 4.5 NM 13 16 309-SALIN-32 Salinas River at Davis Road MBNMS 19 14.8 26 9.0 5 21.8 11 0.0 NM 7 67 309-SALIN-33 Salinas River at Chualar Bridge 17 11 6 8.7 6 21.6 6 0.0 NM 5 56 309-SALIN-44 Salinas River at Curbaril Bridge 13 11 15 8.5 7 21.0 0 10.0 NM 60 0 309-SALIN-45 Salinas River at Old Hwy 58 Bridge 17 9 47 8.5 6 20.0 0 20.0 NM 55 0 Appendix 1.B SSD Twenty Year Report: 2000-2019 WQO Exceedances for Field Measurements

Sites Monitored at Least 5 Years Dissolved Oxygen pH` Water Temperature Turbidity Transparency Maximum % Years % Years Max % Years % Years Maximum Minimum # Years Concentration Exceeded Maximum Exceeded Temperature % Years Exceeded Exceeded (NTU) (cm) Site Code Site Name Sampled (mg/L) WQO WQO (⁰C.) Exceeded WQO WQO WQO 309-SALIN-46 Salinas River San Miguel at Estralia Rock 10 12 20 8.5 0 22.0 18 10.0 NM 60 0 309-SALIN-47 Salinas River at 13th Street bridge in Paso Robles 11 11 27 8.4 0 19.7 0 10.0 NM 50 0 309-SKYLI-31 Skyline at Forest Knoll Road 9 10 11 8.5 11 21.3 13 NM 8 57 309-SMARG-41 Santa Margarita Creek at El Camino Real and Asuncion Road 17 10 41 8.3 0 17.5 0 40.0 NM 60 0 309-SRITA-32 Santa Rita Creek at Bellizona 10 12 40 7.0 10 20.9 0 NM 1 60 309-SRITA-33 Santa Rita Creek at the 14th hole Salinas Valley Golf Course 6 10.54 0 8.5 0 20.5 0 NM 1 83 309-SRITA-34 Santa Rita Creek at Russell Road 11 12 27 8.0 17 24.1 8 NM 2 67 309-SRITA-35 Santa Rita Creek at Van Buren Avenue 11 11.52 18 8.0 0 26.5 58 NM 2 100 309-TEMBL-31 Tembladero Slough at Monterey Dunes 19 12.6 21 8.0 5 21.8 11 NM 0 100 309-TEMBL-32 Tembladero Slough Hwy 183 17 13.6 12 8.5 0 24.0 6 NM 0 88 309-TEMBL-33 Tembladero Slough at Preston Bridge 15 12 13 8.5 7 20.9 0 NM 0 100 309-TIV-31 16 8.4 69 7.8 12 16.7 0 NM 5 50 309-TROUT-41 Trout Creek at 3 bridges 19 9 32 8.5 17 15.5 0 60.0 NM 60 0 309-UPPER-31 Natividad Creek upper 15 13 13 7.8 6 21.5 14 NM 4 73 309-VETER-31 Veteran's Park at big turn in Veterans Drive 15 8.6 53 7.0 0 18.0 0 15.0 NM 45 0 309-YERBA-41 Yerba Buena Creek at Estrada and Hwy 58 9 7 89 7.5 0 15.8 0 10.0 NM 47 0 310-ARROY-41 Arroyo del Puerto at bridge in San Simeon 13 12 23 8.0 0 17.2 0 5.0 NM 44 0 310-ARROY-42 Arroyo de la Cruz under Hwy 1 14 10 43 8.0 0 17.3 0 5.0 NM 48 0 310-CARPO-41 San Carpoforo Creek upstream of mouth 14 10 36 7.5 14 15.6 0 NM 48 0 310-DAL-41 Dairy Creek lower at Dairy Creek Road 6 10.76 0 7.9 0 17.5 0 0.9 0 NM 310-LAGUN-41 Arroyo Laguna mouth 11 10 27 8.0 0 22.1 9 NM 15 18 310-LITTL-41 Little Pico Creek at Hwy 1 8 9.5 25 8.0 0 16.1 0 5.0 NM 117 0 310-PENN-41 Pennington Creek 10 10.94 0 8.4 0 16.1 0 10.0 0 NM 310-PICOC-41 Pico Creek under Hwy 1 Bridge 12 10.6 33 7.5 0 16.8 0 1.9 NM 120 0 310-SANSI-41 San Simeon Creek at campground bridge 18 12 50 8.0 0 16.4 0 3.0 NM 56 0 310-SANSI-42 San Simeon Creek at Red Mountain Road 5 10 40 7.5 0 20.5 0 NM 120 0 310-SANTA-41 Santa Rosa Creek at Hwy 1 MBNMS 17 12.6 12 8.3 0 16.6 0 10.0 NM 114 0 310-SANTA-42 Santa Rosa Creek at Ferrasci Road 15 11.8 13 8.0 0 16.0 0 10.0 NM 120 0 310-SANTA-43 Santa Rosa Creek at Windsor 10 9.5 10 8.0 0 16.1 0 NM 100 0 310-SBE-41 San Bernardo Creek 7 11.88 0 8.0 0 17.5 0 3.3 0 NM 310-SYB-41 Santa Ysabela Creek on Turri Road 13 15.78 54 8.1 0 24.0 15 50.5 8 NM 310-UCF-41 Upper Chorro Flats at Chorro Creek and Morro Creek Roads 13 13.23 8 8.4 0 16.7 0 2.2 0 NM 317-ESTRE-43 Estrella River at Whitley Gardens 6 12 0 8.5 0 27.4 43 9.0 NM 56 0