BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY 2014 UPDATE
FINAL REPORT
Prepared for: City of St. Helena
Prepared by:
FEBRUARY 2014
Bell Canyon Reservoir Watershed Sanitary Survey Third Update FINAL REPORT February 2014
Prepared for: City of St. Helena
Prepared by: Leslie Palencia, Palencia Consulting Engineers
TABLE OF CONTENTS
Page Number Executive Summary Introduction ...... ES-1 Objectives of the Update ...... ES-1 Key Findings and Conclusions ...... ES-1 Source Water Quality ...... ES-1 Turbidity ...... ES-2 Coliform ...... ES-2 Disinfection By-Product Precursors ...... ES-3 Intake Evaluation ...... ES-3 Turbidity ...... ES-3 Microbiological Constituent Review ...... ES-3 Disinfection By-Products and Precursors ...... ES-4 Giardia/Virus/Cryptosporidium Reduction Requirements ...... ES-4 Watershed Contaminant Sources ...... ES-5 Spills ...... ES-5 Wineries/Vineyards ...... ES-5 Unauthorized Activity ...... ES-5 Storm Water ...... ES-6 Septic Systems ...... ES-6 Fires ...... ES-6 Recommendations ...... ES-7
Section 1 – Introduction
Introduction ...... 1-1 Objectives of the Update ...... 1-1 Constituents and Potential Contaminating Activities Covered in the Third Update ...... 1-2 Description of How the Third Update was Conducted ...... 1-3 Report Organization ...... 1-3
Section 2 – Watershed and Water Supply Systems
Watershed Description ...... 2-1 General Description and Stream Flow ...... 2-1 Land Use and Population ...... 2-2 Climate and Precipitation ...... 2-2 Water Supply System – City of St. Helena ...... 2-2 Service Area and Sources ...... 2-3 Water Treatment ...... 2-3
Section 3 – Bell Canyon Reservoir Water Quality Review
Overall Water Quality Review ...... 3-1
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Selected Constituent Review ...... 3-2 Turbidity ...... 3-2 General Characteristics and Background ...... 3-2 Evaluation ...... 3-3 Summary of Results...... 3-4 Microbiological Constituents ...... 3-4 General Characteristics and Background ...... 3-4 Evaluation for Total Coliform and E. coli ...... 3-6 Summary of Results for Total Coliform and E. coli ...... 3-8 Disinfection By-Product Precursors (Total Organic Carbon) ...... 3-9 General Characteristics and Background ...... 3-9 Evaluation ...... 3-9 Summary of Results...... 3-9 Algalloo 3 Detectable Title 22 Constituents of Interest 3- Detectable Title 22 Constituents of Interest ...... 3-10
Section 4 – Watershed Contaminant Sources Review
Spills ...... 4-1 Background ...... 4-1 Seasonal Patterns ...... 4-1 Related Constituents ...... 4-1 Occurrence in Watershed ...... 4-1 Related Water Quality Issues and Data Review ...... 4-2 Regulation and Management ...... 4-2 Recommended Source Water Protection Activities ...... 4-2 Wineries/Vineyards ...... 4-3 Background ...... 4-3 Seasonal Patterns ...... 4-3 Related Constituents ...... 4-3 Occurrence in Watershed ...... 4-3 Sewage System Monitoring Permit ...... 4-5 Erosion Control Plan ...... 4-6 Crops and Pesticide Use ...... 4-7 Related Water Quality Issues and Data Review ...... 4-7 Regulation and Management...... 4-7 Recommended Source Water Protection Activities ...... 4-8 Unauthorized Activity ...... 4-9 Background ...... 4-9 Occurrence in Watershed ...... 4-9 Related Water Quality Issues and Data Review ...... 4-9 Regulation and Management...... 4-11 Recommended Source Water Protection Activities ...... 4-11 Storm Water ...... 4-12 Background ...... 4-12 Seasonal Patterns ...... 4-12 Occurrence in Watershed ...... 4-23
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Storm Water Pollution Prevention Plan – County of Napa ...... 4-12 General Industrial Storm Water Permit - SWRCB ...... 4-13 Related Water Quality Issues and Data Review ...... 4-13 Regulation and Management...... 4-14 Recommended Source Water Protection Activities ...... 4-14 Septic Systems ...... 4-15 Background ...... 4-15 Related Constituents ...... 4-15 Occurrence in Watershed ...... 4-15 Related Water Quality Issues and Data Review ...... 4-16 Regulation and Management...... 4-16 Recommended Source Water Protection Activities ...... 4-16 Fires ...... 4-17 Background ...... 4-17 Seasonal Patterns ...... 4-17 Related Constituents ...... 4-17 Occurrence in Watershed ...... 4-17 Related Water Quality Issues and Data Review ...... 4-18 Regulation and Management...... 4-18 Recommended Source Water Protection Activities ...... 4-18
Section 5 – Intake Evaluation
Louis Stralla Water Treatment Plant...... 5-2 System Description ...... 5-2 Water Quality Summary ...... 5-2 Turbidity ...... 5-2 Microbiological Constituent Review ...... 5-3 Disinfection By-Products and Precursors...... 5-3 Volatile and Synthetic Organic Compounds ...... 5-8 Detectable Title 22 Constituents ...... 5-8 Giardia/Virus/Cryptosporidium Reduction Requirements ...... 5-8 Regulatory Compliance Evaluation ...... 5-8
Section 6 – Recommendations
Appendix A – Bibliography and List of Contacts Appendix B – Summary of the Louis Stralla Water Treatment Plant Intake data Appendix C – Bell Canyon Reservoir Watershed Map
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LIST OF TABLES
Page Number
Table 1-1 Water Quality Constituents Selected for Evaluation as Part of the Third Update ...... 1-2
Table 3-1 Summary of Raw Water Quality Data for the Louis Stralla WTP .. 3-1 Table 3-2 Relationship Between Potential Contaminating Activities and Water Quality ...... 3-2 Table 3-3 Manganese and Iron Levels in Bell Canyon Reservoir, 2009-2013 ...... 3-11
Table 4-1 Wineries and Vineyards in Bell Canyon Reservoir Watershed as of 2013 ...... 4-4 Table 4-2 Wineries/Vineyards in Bell Canyon Reservoir Watershed- Summary of Permits and Plan Regulated by County ...... 4-5 Table 4-3 Wineries/Vineyards in Bell Canyon Reservoir Watershed with Sewage System Monitoring Permits ...... 4-6 Table 4-4 Pesticide and Herbicide Usage in Napa County on Wine Grapes in 2012...... 4-7 Table 4-5 Storm Water Sampling Results from Arkenstone Vineyards, 2010-2012 ...... 4-13 Table 4-6 Septic System Violations in Bell Canyon Reservoir Watershed 2009-2012 ...... 4-15
Table 5-1 TOC Enhanced Coagulation Removal Requirements (Percent) .. 5-4 Table 5-2 Enhanced Coagulation Removal Requirements at Louis Stralla WTP, 2009-2013 ...... 5-5 Table 5-3 Regulatory Compliance Evaluation City of St. Helena Louis Stralla WTP ...... 5-9
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LIST OF FIGURES
Page Number
Figure 2-1 Calculated Inflows for Bell Canyon Reservoir, 2009-2013 ...... 2-1 Figure 2-2 Monthly Rainfall Totals at Bell Canyon Reservoir, 2009-2013 ...... 2-3
Figure 3-1 Plant Influent Peak Daily Turbidity and Precipitation for the Louis Stralla WTP 2009-2013...... 3-4 Figure 3-2 Total Coliform for Bell Canyon Reservoir, 2009-2013 ...... 3-7 Figure 3-3 E. coli for Bell Canyon Reservoir, 2009-2013 ...... 3-8 Figure 3-4 Monthly TOC and Precipitation at the Louis Stralla WTP, 2009-2013 ...... 3-10
Figure 4-1 Bell Canyon Reservoir, looking from Burgess Cellars Vineyard ...... 4-4 Figure 4-2 Shooting Range with Bell Canyon Reservoir in Background ...... 4-10 Figure 4-3 Shooting Range in Bell Canyon Reservoir Watershed ...... 4-10
Figure 5-1 Louis Stralla WTP – Raw, Settled, and Treated Water Turbidities, 2009-2013 ...... 5-3 Figure 5-2 Louis Stralla WTP- Raw and Treated TOC ...... 5-4 Figure 5-3 City of St. Helena Distribution System TTHMs for Sites 2 and 6. January 2009-December 2013 ...... 5-7 Figure 5-4 City of St. Helena Distribution System HAA5s for Sites 2 and 6. January 2009-December 2013 ...... 5-8
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LIST OF ABBREVIATIONS
AF – acre-feet Alum - aluminum sulfate
BAT – Best Available Technology BCT – Best Conventional Control Technology BMP – Best Management Practice BOD – Biological Oxygen Demand
CALFIRE- California Dept. of Forestry CAP – Cryptosporidium Action Plan CCR – Consumer Confidence Report CDPH – California Department of Public Health cfs – cubic feet per second CIWQS – California Integrated Water Quality System CT – Contact Time CUPA – Certified Unified Program Agency
D/DBP – Disinfectants/Disinfection By-Products DBP – disinfection by-product
E. coli – Escherichia coli gpd – gallons per day gpm – gallons per minute
HAA5 – haloacetic acids
IDSE – Initial Distribution System Evaluation IESWTR – Interim Enhanced Surface Water Treatment Rule IFE – individual filter effluent
LRAA – locational running annual average LT1ESWTR – Long Term 1 Enhanced Surface Water Treatment Rule LT2ESWTR – Long Term 2 Enhanced Surface Water Treatment Rule
MCL – maximum contaminant level µg/L - micrograms per liter mgd – million gallons per day mg/L – milligrams per liter MPN/100 mL – most probable number per 100 milliliters MS4 – Municipal Separate Storm Water System
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NPDES – National Pollution Discharge Elimination System NTU – nephelometric turbidity unit
OES – California Office of Emergency Services
PCSs – Potential Contaminant Sources
RAA – running annual average Regional Board – San Francisco Regional Water Quality Control Board RCD – Resource Conservation District RIMS – Response Information Management System
SDWA – Safe Drinking Water Act SEMS – Standardized Emergency Management System SIC – Standard Industrial Classification SMARTS – Storm Water Multiple Application and Report Tracking System SOC – synthetic organic compound SSO – Sanitary Sewer Overflow SWPPP – Storm Water Pollution Preventation Plan SWRCB – State Water Resources Control Board SWTR – Surface Water Treatment Rule
TOC – total organic carbon TTHM – total trihalomethanes ug/L – micrograms per liter USEPA – US Environmental Protection Agency UV – Ultraviolet light
VOC – volatile organic compound
WDR – Waste Discharge Requirement WTP –Water Treatment Plant WWTP – Wastewater Treatment Plant
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page vii 2014 UPDATE – FINAL REPORT EXECUTIVE SUMMARY
INTRODUCTION
Drinking water utilities that use surface water are required to conduct a watershed sanitary survey for that source, under the California Surface Water Treatment Rule (SWTR). This survey must be updated every five years. This Third Update to the Bell Canyon Reservoir Watershed Sanitary Survey covers the period January 1, 2009 through December 31, 2013.
OBJECTIVES OF THE UPDATE
The overall objective of this Third Update is to assess the source water quality of Bell Canyon Reservoir to ensure the ability of the Louis Stralla Water Treatment Plant (WTP) to continue to provide their customers with drinking water that meets all current drinking water standards. This Third Update also accomplishes some other specific objectives including:
Review and evaluation of selected constituents of interest to identify potential water quality or treatment issues at the water treatment plant. Assess the ability of the Louis Stralla WTP to meet drinking water standards based on current regulatory framework, as well as comment on the appropriate level of treatment for pathogens, specifically for Giardia, viruses, and Cryptosporidium.
Review and evaluation of selected potential contaminating activities in the watershed to identify potential impacts on source water quality, if any.
Development of recommendations that are economically feasible and within the authority of the City of St. Helena (City) to implement.
KEY FINDINGS AND CONCLUSIONS
The key findings and conclusions for this report are organized as they pertain to source water quality, treatment and regulatory compliance, and watershed contaminant sources. Highlights of these findings and conclusions are presented below.
Overall, there have been no significant changes in the watershed since the 2009 Update. Additionally, the Louis Stralla WTP has not undergone any significant treatment upgrades since the 2009 Update.
Source Water Quality
Overall, Bell Canyon Reservoir provides good quality raw water. The raw water can be treated to meet all drinking water standards using conventional treatment processes. The only constituent present in the raw water that consistently
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EXECUTIVE SUMMARY requires additional treatment is manganese. Key findings for the constituents of interest are presented below.
Turbidity
The Louis Stralla WTP has low levels of raw water turbidity, with average values less than 4 NTU. The peak daily raw water turbidities ranged from 1.5 to 12.2 nephelometric turbidity units (NTU). It should be noted that the raw water turbidities are a monthly average of peak daily grab samples. Most turbidity peaks generally occur during the wet season, between December and March. The highest monthly turbidities occurred in the months of February or March for four years out of the five year reporting period.
Coliform
Individual total coliform and E. coli samples had average values of 855 most probable number (MPN)/100 mL, and 2.2 MPN/100 mL respectively. There were many months where total coliform levels were greater than 2,420 MPN/100mL, which is the maximum detectable concentration for the laboratory. High total coliform values tend to occur in March and May, although occasionally in October and November. High total coliform values occur during months of heavy precipitation, but can also occur during months of no precipitation. Although the cause of high total coliform is undetermined, it may be related to algal blooms occurring in the spring and fall.
E. coli data show generally low levels, with no seasonal trends evident. The highest E. coli measurement was 40.4 MPN/100mL which occurred in August 2013. The current permit issued by the California Department of Public Health (CDPH) specifies that in the event the E. coli is greater than 1,000 MPN/mL, an additional log removal of Giardia is required. Since 100 percent of the E. coli samples were less than 1,000 MPN/mL, no additional log removal is required.
Therefore, E. coli data continue to support 3/4-log treatment for Giardia/viruses for all source water quality conditions during the study period.
The City conducted Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) monitoring from October 2008 to September 2009. As a Schedule 4 system, the City conducted E. coli biweekly sampling for one year. The average for this dataset was 1.98 MPN/100mL, well below the risk threshold of 10 MPN/100mL for a lake source under LT2ESWTR. This indicates that the system is not considered to be potentially at risk for microbial contamination and was not required to conduct source water monitoring for Cryptosporidium. In 2013, the City received an email from the CDPH indicating that the Louis Stralla WTP was classified as Bin 1 for the LT2ESTWR.
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EXECUTIVE SUMMARY
Disinfection By-Product Precursors
Total organic carbon (TOC) data for the Bell Canyon Reservoir source is always above 2 mg/L, with an average level of 4.7 mg/L over the reporting period. Similar to turbidity, increases in TOC appears to be correlated with high precipitation. The highest monthly TOC levels occurred in the months of February or March for three years out of the five year reporting period.
Intake Evaluation
Louis Stralla Water Treatment Plant
The Louis Stralla WTP is currently in compliance with all existing drinking water regulations. The Louis Stralla WTP implements conventional filtration processes and meets all current drinking water standards, including maximum contaminant levels (MCLs) and treatment technology requirements. Below is a summary of the selected treatment and regulatory compliance issues.
Turbidity
All filter effluent turbidity measurements between January 2009 and December 2013 met the turbidity treatment technique limit and were less than 0.06 NTU. The settled water turbidities had an average value of 1.2 NTU and the average daily Filter #1 and Filter #2 effluent turbidities had an average value of 0.04 NTU. It should be noted that the settled water turbidities are a monthly average of peak daily grab samples, and the filter effluent turbidities are a monthly average of a daily average, based on all 4-hr samples in a 24 hour period.
The average solids removal from raw to settled water was 69 percent over the period of study, and the average solids removal from raw to treated was 98.9 percent. Removal from raw to settled is most difficult under low alkalinity raw water periods, as in February 2013.
Microbiological Constituent Review
Distribution system monitoring for coliforms as part of the Total Coliform Rule resulted in a single detection of total coliform in the distribution system reported on the 2011 and 2012 Consumer Confidence Reports during the study period. In each month with a detect, less than five percent of samples were positive and there were no fecal coliform detected. Therefore, there were no violations of the coliform MCL.
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EXECUTIVE SUMMARY
Disinfection Precursors and By-Products
The Louis Stralla WTP effluent data show an average TOC value of 2.1 mg/L, with 64 percent of treated water samples greater than 2.0 mg/L. For source or treated waters with a running annual average (RAA) TOC greater than 2.0 mg/L, the TOC removal ratio is required to be calculated to comply with Step 1 of the Enhanced Coagulation treatment technique of the Stage 1 Disinfection/Disinfection Byproduct (D/DBP) Rule. For the Bell Canyon Reservoir source, the TOC is generally between 4 and 8 mg/L and the source water alkalinity is below 60 mg/L, therefore 45 percent TOC removal is required. As shown in Section 5, the Louis Stralla WTP is complying with the Step 1 TOC removal requirements in 58 out of 60 months. Although the TOC removal requirements were not met in January 2009 and December 2009, the running annual average for TOC removal ratio was met and the WTP is in compliance with the Step 1 TOC removal requirements.
Under the Stage 1 D/DBP Rule, the City sampled six sites in the distribution system for total trihalomethanes (TTHM) and haloacetic acids (HAA5) on a quarterly basis from January 2009 to August 2012. Between January 2009 and August 2012, the TTHM RAA ranged from 57.1 to 74 μg/L, with an average of 67.3 μg/L. The HAA5 RAA ranged from 37.9 to 56.5 μg/L, with an average of 49.8 μg/L. Over this reporting period, RAAs are well below the MCLs per the Stage 1 D/DBP Rule.
The City converted to the two Stage 2 D/DBP monitoring sites in November 2012. Both sites are existing Stage 1 sites. TTHM locational running annual average (LRAAs) ranged from 55 to 59 μg/L for Site 2 (3029 St. Helena Hwy) and ranged from 58 to 62 μg/L for Site 6 (Knoll Place). HAA5 LRAAs ranged from 48 to 55 μg/L for site 2, and from 53 to 55 μg/L for site 6. Over the reporting period, LRAAs are well below the TTHM and HAA5 MCLs per the Stage 2 D/DBP Rule.
Giardia/Virus/Cryptosporidium Reduction Requirements
Based on the E. coli data presented in Section 3, 3/4/2-log reduction of Giardia/virus/Cryptosporidium appear to be appropriate reduction requirements for the Louis Stralla WTP under all source water quality scenarios.
The Louis Stralla WTP is classified as a conventional filtration WTP, and currently receives reduction credit for 2.5-log Giardia, 2.0-log viruses, and 2-log Cryptosporidium for physical removal. Disinfection with sodium hypochlorite provides 0.5-log credit for Giardia and 2.0-log credit for viruses. This meets all of the current microbial removal/inactivation requirements of the SWTR and the Interim Enhanced SWTR.
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EXECUTIVE SUMMARY
Watershed Contaminant Sources
There are numerous types of potential contaminating activities (PCAs) in the watershed. Six activities were selected for evaluation in this report based on constituents of interest and predominance in the watershed. Selected findings for each of these activities are provided below.
Spills
Spill information was queried from the Office of Emergency Services (OES) Response Information Management System (RIMS) archived database and the State Water Resources Control Board’s (SWRCB) California Integrated Water Quality System (CIWQS) database on sanitary sewer overflows (SSOs).
The OES’ RIMS database did not contain any spills in the watershed from 2009 through 2013 and the SWRCB’s CIWQS database did not contain any SSOs from private laterals.
Wineries/Vineyards
According to the Napa County Environmental Health Division, there are eight active producing vineyards in the watershed, with another winery pending approval and two wineries approved to begin production. The total vineyard acreage in the watershed is 262 acres, which was 244 acres in the 2009 Update. The parcels owned by Viader and Burgess are of most concern due to their proximity to the Bell Canyon Reservoir and they appear to be on a steep grade.
Wineries and vineyards may be required to have a permit or plan from Napa County under the areas of sewage system monitoring, erosion control and storm water. Each of the respective departments in Napa County was contacted for information. Wineries with active erosion control plans are inspected every year prior to the rainy season, and wineries with sewage system monitoring permits are inspected every other year. Overall, the County did not identify any specific issues related to septic systems or erosion to impact Bell Canyon Reservoir. Storm water will be discussed below.
Unauthorized Activity
Typical unauthorized activities that may be potential contaminant sources are illegal dumping, illegal camping and unsanctioned recreational activities. Bell Canyon Reservoir is not open to the public for recreation. On occasion, there is unauthorized swimming, but City staff believe this is occurring less compared to 5 to 10 years ago. Primarily, there is litter and painting of graffiti on the spillway.
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EXECUTIVE SUMMARY
Although it is not an unauthorized activity, there is a shooting range owned by the City of St. Helena Police Department. The City is evaluating options to remove bullets from the site which could leach contaminants such as arsenic and lead.
Storm Water
Wineries are inspected by Napa County for stormwater compliance every three years. Out of the eight active wineries/vineyards in the watershed, only three are inspected for stormwater, as the other facilities have a covered crush pad and are not required to have a stormwater pollution prevention plan. A review of the most recent inspection reports for Ladera, Neal Family Vineyards and Arkenstone showed that the facilities were in compliance for stormwater.
As required by the SWRCB’s General Industrial Activities Storm Water Permit, the Arkenstone Vineyards is required to sample two storm events per year. Over the reporting period, three storm events on December 27, 2010, March 16, 2012 and December 3, 2012 were sampled. Based on these limited analyses, storm water discharges from wineries and vineyards can be a source of turbidity, TOC and salinity.
Septic Systems
The number of septic systems in the watershed was estimated, based on the number of parcels, as the County does not have a historical database for total septic systems. The Napa County Department of Planning, Building and Environmental Services agreed that an estimate of 100 septic systems in the watershed would be an estimate on the high side as some of the parcels are vineyards or undeveloped.
There were two reports of septic system failure in the watershed in February 2010 and April 2012. However, the sewage did not reach any surface waters.
Fires
The Bell Canyon watershed is characterized as Very High Fire Hazard Severity Zone by CALFIRE. According to the historical fire database on the CALFIRE website, there were no fires which occurred within the study watershed since 2009. Fires smaller than 300 acres were not included in the database.
Overall, fires and vineyards/wineries continue to be watershed activities of most concern in the Bell Canyon watershed. The County is involved in various aspects of vineyard/winery operation, which helps to protect Bell Canyon Reservoir from erosion, storm water, and septic system impacts.
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EXECUTIVE SUMMARY
RECOMMENDATIONS
A number of recommendations covering water quality and watershed management were developed for this Third Update. Please refer to Section 6 for further information on the recommendations.
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SECTION 1 - INTRODUCTION
INTRODUCTION
This report presents the findings of the Third Update to the Bell Canyon Reservoir Watershed Sanitary Survey. This study covers the period January 1, 2009 through December 31, 2013. The Second Update was completed in February 2009 (2009 Update), the First Update was completed in 2003 (2003 Update), and the initial Watershed Sanitary Survey was completed in 1996 in accordance with the California Surface Water Treatment Rule (SWTR).
For assistance with abbreviations and acronyms, the reader is referred to the List of Abbreviations at the front of the report.
OBJECTIVES OF THE UPDATE
A watershed sanitary survey focuses on the first barrier to contamination of the drinking water supply, namely source water protection. Evaluating source water quality and watershed contaminant sources provides key information to aid in understanding how to maintain and possibly improve the first barrier. In order to fully assess the ability of the City of St. Helena (City) to treat Bell Canyon Reservoir water, some evaluation of treatment plant capabilities and treated water quality is also necessary.
This Third Update is intended to accomplish the following objectives:
1) Fulfillment of the California SWTR and the Interim Enhanced Surface Water Treatment Rule (IESWTR) requirements that surface water agencies conduct a watershed sanitary survey of the source watershed once every five years. Any significant changes within the last five years that affect source water quality are to be identified in each update. In addition, it is required to comment on the appropriate level of treatment for pathogens, specifically for Giardia, viruses, and Cryptosporidium.
2) Review and evaluation of selected constituents of interest to identify potential water quality or treatment issues at the Louis Stralla Water Treatment Plant (WTP). Assess the ability of the treatment plant to meet standards based on current regulatory framework.
3) Review and evaluation of selected potential contaminating activities to identify impacts on source water quality. Determine whether it may be useful to conduct additional monitoring to further assess contaminant levels in the source water or contaminants from a particular watershed source.
4) Identification of appropriate watershed management actions to protect and possibly improve source water quality. Development of recommendations for watershed management actions that are economically feasible and within the authority of the City to implement is critical.
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CONSTITUENTS AND POTENTIAL CONTAMINATING ACTIVITIES COVERED IN THE THIRD UPDATE
Several water quality constituents were selected for evaluation as part of the Third Update. Table 1-1 presents a summary of the water quality constituents selected and the reason for selection.
Table 1-1. Water Quality Constituents Selected for Evaluation as Part of the Third Update
Constituent Reason for Inclusion in Third Update Turbidity Turbidity is a measurement of suspended solids in water. Treated water turbidity levels are regulated in the SWTR and the IESWTR. Total Coliform As stated in the current permit, total coliform should be monitored monthly. E. coli E. coli are more specific surrogates for fecal contamination. As stated in the current permit, E. coli should be monitored monthly to determine appropriate level of treatment for Giardia. Total Organic Carbon Total organic carbon (TOC) is a surrogate measure of disinfection by-products (DBP) precursor material in water. TOC levels in either source or treated water are used to determine treatment requirements in the Stage 1 Disinfectant/Disinfection By-Product Rule (D/DBP). Total Trihalomethanes Total Trihalomethanes (TTHMs) are disinfection by- products formed in disinfected treated water. Treated water levels are regulated by the Stage 1 D/DBP Rule and further regulated under the Stage 2 D/DBP Rule. Haloacetic Acids Haloacetic acids (HAA5) are disinfection by- products formed in disinfected treated water. Treated water levels are regulated by the Stage 1 D/DBP Rule and further regulated under the Stage 2 D/DBP Rule.
Six potential contaminating activities were selected for review as part of the Third Update: spills, wineries/vineyards, unauthorized activity, storm water, septic systems, and fires. Each of these activities can contribute at least one of the constituents identified in Table 1-1 to the source water. These activities were selected based on their presence in the watershed, and were identified by the City as key contaminating activities.
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DESCRIPTION OF HOW THE THIRD UPDATE WAS CONDUCTED
The project team consisted of representatives from the City and Palencia Consulting Engineers. The project team participated in developing the scope of work and reviewed identification and development of key findings and recommendations.
Information on the Louis Stralla WTP treatment processes and treatment challenges since the 2009 Update was obtained from the City through a survey form. Raw and treated water quality data was also provided by the City.
Palencia Consulting Engineers collected information on contaminant sources in the watershed through literature reviews, Internet searches, and discussions with various agencies’ staff. A bibliography and list of contacts are provided in Appendix A.
REPORT ORGANIZATION
Section 1 – Introduction
This section describes the objectives of the Third Update, lists the main constituents and potentially contaminating activities covered in the Third Update, describes how the Third Update was conducted, and includes a description of the basic report organization.
Section 2- The Watershed and Supply System
This section is largely descriptive and provides: (1) a brief overview of the physical, hydrologic, and land use characteristics of the watershed, (2) a description of the existing water supply system, and (3) the Louis Stralla WTP treatment processes. For more detailed descriptive information on watershed characteristics, the reader is referred to the 1996 Watershed Sanitary Survey.
Section 3 – Bell Canyon Reservoir Water Quality Review
This section provides a review of the constituents of interest, including an explanation for their selection and a summary of the data obtained for the period of study for each constituent.
Section 4 – Watershed Contaminant Sources Review
This section describes pertinent characteristics of each of the six potential contaminating activities that were reviewed as part of this Third Update. If applicable, each potential contaminating activity will include a discussion on background and occurrence, seasonal patterns, water quality issues and data review, regulation and management, and source water protection activities.
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 1-3 2014 UPDATE – FINAL REPORT SECTION 1 - INTRODUCTION
Section 5 - Intake Evaluation
This section contains an evaluation of the Louis Stralla WTP’s treated water quality, as well as an evaluation of the Louis Stralla WTP’s ability to meet the SWTR as well as other existing regulations.
Section 6 – Recommendations
This section consists of a list of recommendations for future source water protection efforts.
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WATERSHED DESCRIPTION
This section provides an overall description of the watershed, which summarizes physical, hydrologic, and land use characteristics. Major watershed characteristics such as soils, geology, biology, and topography have changed little since the original 1996 Sanitary Survey (CH2MHill, 1996). This section provides a description of the City of St. Helena’s (City) existing water supply system, including a brief description of the Louis Stralla Water Treatment Plant (WTP).
General Description and Stream Flow
The Bell Canyon Reservoir watershed, is a subwatershed of the Napa River watershed and is approximately 3,647 acres, as shown in Appendix C. Bell Canyon Reservoir was formed in 1959 by the construction of Bell Canyon Dam on Bell Creek about two miles upstream of its confluence with the Napa River.
In 2003, the City initiated water balance calculations for Bell Canyon Reservoir, as well as measurements of outflow and evaporation so that inflows into the reservoir via Bell Creek could be calculated. Figure 2-1 shows the calculated inflow in Bell Creek from 2009 to 2013. For this five-year period of record, the average inflow was 4.7 cubic feet per second (cfs), and the median inflow was 0.6 cfs. The highest calculated inflow was on December 23, 2012 at 516.5 cfs. As expected, higher flows occur during the wet winter season, generally from December through March, with reduced flows during the remaining months.
Figure 2-1. Calculated Inflows for Bell Canyon Reservoir, 2009-2013
BELL CANYON RSERVOIR WATERSHED SANITARY SURVEY Page 2-1 2014 UPDATE – FINAL REPORT SECTION 2 – WATERSHED AND WATER SUPPLY SYSTEM
Bell Canyon Reservoir has a capacity of 2,250 acre-feet (AF). The safe yield is estimated at about 800 to 1,000 AF. The surface area is approximately 76 acres. The maximum water surface elevation is 422 feet. At this elevation the water depth at the dam is about 60 feet. Water rights permits allow the City to divert 1800 AF between November 15 and April 15 of each year. Additional water rights allow the City to store another 2,000 AF in the reservoir, subject to a schedule of minimum releases for the protection of downstream fish as required by the California Department of Fish and Game. The lake is generally at capacity during the wet season and is then slowly drawn down to its lowest level, generally in October of each year.
The watershed has steep slopes and deep valleys and is largely undeveloped. According to a 2012 report published by the San Francisco Estuary Institute, the dominant geologic type is Sonoma volcanics, and the mean slope of the Bell Canyon watershed is 24.5 to 32.7 percent (San Francisco Estuary Institute, 2012).
Land Use and Population
The major land uses are agriculture (approximately 262 acres of vineyards), recreation/open space, and a small amount of rural residential. There are no incorporated cities within the watershed. There is one small town, Angwin, in the eastern portion of the watershed where the topography is flatter. According to the 2010 Census, the total population of Angwin was 3051. This is a slight decrease (3 percent) in population from 2000, when the population was 3148. Most of the town is located in the Lake Hennessey watershed with only a minor portion of Angwin in the Bell Canyon Reservoir watershed. The area is becoming popular with winemakers to plant vineyards and build wineries.
The City owns 140.7 acres around, and including, the lake. Most of the remainder of the watershed is privately owned. A field visit conducted in November 2013 found no commercial businesses in the watershed except for wineries.
Climate and Precipitation
In general, the Napa River watershed has a number of mesoclimates. These range from moderate, fog-influenced, lower rainfall areas to high rainfall areas. Figure 2-2 shows monthly precipitation totals from the City’s rain gauge at Bell Canyon Reservoir from January 2009 through December 2013. The highest monthly rainfall total was 14.3 inches in December 2012. The average annual precipitation from 2009 to 2013 was 32.3 inches. Over the period of record, from 1983 to 2013, the average annual precipitation was 36.7 inches. It is also important to note that calendar year 2013 was the driest year on record since 1983, with 7.4 inches of precipitation.
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Figure 2-2. Monthly Rainfall Totals at Bell Canyon Reservoir, 2009-2013
WATER SUPPLY SYSTEM – CITY OF ST. HELENA
Service Area and Sources
The City provides treated drinking water to a population of approximately 5,800 within the City limits and the surrounding rural area through 2,447 active service connections. As of December 2013, there are 2,140 residential, 268 commercial, 18 industrial, 15 agricultural, and 6 other connections. The City has three sources of water: Bell Canyon Reservoir provided 54.4 percent, the City of Napa supplied 35.4 percent, and the Stonebridge Wells provided 10.2 percent in 2012.
Water Treatment
Water from Bell Canyon Reservoir is treated at the Louis Stralla WTP. The WTP has a maximum capacity of 3.5 million gallons per day (MGD). Currently the average flow through the plant is 0.64 MGD in winter and 0.92 MGD in summer. The WTP began operation in 1980 and was upgraded in 1995. The plant provides complete conventional treatment including chemical addition, flash-mixing, dual train flocculation and sedimentation, multi-media rapid sand filtration, and disinfection.
Diversion Structure. Water is diverted from the lake through an intake tower that has outlets at 400, 385 (out of service), and 370.5 feet. In order to break up lake
BELL CANYON RSERVOIR WATERSHED SANITARY SURVEY Page 2-3 2014 UPDATE – FINAL REPORT SECTION 2 – WATERSHED AND WATER SUPPLY SYSTEM stratification and provide additional mixing, the lake is aerated with an aerator located approximately five feet from the bottom of the reservoir. This increases the dissolved oxygen concentrations so that manganese formation is minimized. Water is conveyed by gravity from Bell Canyon Reservoir by a 24-inch diameter steel pipeline that travels 0.17 mile to where it ties into an 18-inch concrete lined steel pipeline. The 18-inch pipeline runs 0.32 mile and connects to the influent structure at the Louis Stralla WTP.
In February 2009, it was discovered that the mid-intake valve at 385 feet was inoperable during an inspection. From February 2009 to October 2012, the valve was stuck open, despite two attempts in 2010 to repair the valve. In October 2012, a cofferdam patch was secured and the valve was closed.
Influent Chemical Addition. The City is currently injecting alum at the flash mix diffuser, and nonionic polymer at the applied water channel before the flocculators. Sodium permanganate is added as a pre-treatment step at the reservoir to remove manganese. However, extensive testing in winter 2012 discovered that applying a minimum 0.5 mg/L free chlorine dose in the filter effluent was most effective in removing manganese during the treatment process.
Flocculation and Sedimentation. Flocculation and sedimentation occur in two parallel treatment trains. After chemical addition, water flows into two high velocity flocculation basins and then into the two low velocity basins. The water then flows into two parallel sedimentation basins. Settled floc is removed by siphon-operated sludge collectors and discharged to one of two reclaimed water basins. Sodium hypochlorite is applied at the sedimentation basin effluent channel. As stated above, it was discovered that maintaining a minimum 0.5 mg/L free chlorine dose in the filter effluent allows the filter to remove more manganese. During periods of low alkalinity in the source water, non-ionic polymer is added at the sedimentation basin effluent as a filter aid.
Filtration. Clarified water flows through two multi-media gravity filters. The media consists of 18 inches of anthracite over 9 inches of silica sand and 3 inches of garnet gravel supported by 10 inches of support gravel. Filter backwash water is discharged to one of two reclaimed water basins. The yearly average filtration rate is 1.6 gpm/square foot. Backwash is initiated by either high headloss (84 inches), run time (72 hours), or if turbidity starts to rise.
Disinfection. Sodium hypochlorite is added to the filtered water prior to the clearwell for disinfection. The chlorination dose rate is controlled automatically to maintain a pre-set chlorine residual leaving the clearwell. The average free chlorine dose is 3.0 mg/L.
Post Chemical Addition. Sodium hydroxide and orthophosphate are injected to the filtered water prior to the clearwell. Sodium hydroxide is used to adjust the pH to 7.0 to 7.3 in the clearwell. Orthophosphate is added for corrosion control at a dose of 1.7 to 2.1 mg/L to maintain a 1.0 mg/L residual in Tank No. 1.
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Backwash Clarification Basins. As stated earlier, the sedimentation basin sludge and filter backwash water are discharged to one of two reclaimed water basins. The other reclaimed water basin is for sludge dewatering. When the basin is full of sludge, it is taken off line and the sludge is pumped to the earthen basin sludge lagoon where it is dried. Dried sludge is taken to a landfill in Calistoga. The clarified water is recycled to the plant headworks.
Storage Facilities. The treated water is stored onsite in an 80,500 gallon baffled concrete clearwell. Water is pumped from the clearwell through a 16-inch steel transmission line to the 1.4 million gallon Tank No. 1. In December 2011, the City was directed by the California Department of Public Health to recoat or replace Tank No. 1. The City chose to replace the tank, which is currently under construction.
BELL CANYON RSERVOIR WATERSHED SANITARY SURVEY Page 2-5 2014 UPDATE – FINAL REPORT SECTION 3 – BELL CANYON RESERVOIR WATER QUALITY REVIEW
This section provides an overall review of the water quality data available for Bell Canyon Reservoir. There were no other ambient water quality monitoring data available, other than data collected by the City of St. Helena (City). Therefore, overall water quality review will be based on the data collected by the City. The study period was defined as January 1, 2009 through December 31, 2013. Appendix B contains a summary of the Louis Stralla Water Treatment Plant (WTP) intake data used for this review.
This section also provides a review of the constituents of interest, including an explanation for their selection and a summary of the data obtained during the study period.
For assistance with abbreviations and acronyms, the reader is referred to the List of Abbreviations at the front of the Report.
OVERALL WATER QUALITY REVIEW
The review of overall water quality is based on comparison of the Louis Stralla WTP intake water (also called raw water) to drinking water standards for the constituents currently regulated. This includes all constituents with primary and secondary Maximum Contaminant Levels (MCLs) and unregulated constituents that have Notification Levels. In general, it is assumed that if the raw water is below these limits, then the treated water (also called finished water) will be also. MCLs and Notification Levels are typically based on treated water sample results.
Overall, Bell Canyon Reservoir provides good quality water. The raw water is treated to meet all primary drinking water standards using conventional filtration processes. The only constituent present in the raw water that consistently requires additional treatment is manganese. The individual intake evaluation for treated water and regulatory compliance is presented in Section 5.
Selected raw water data has been summarized and is included in the summary table below. Table 3-1 shows the statistics for each selected constituent.
Table 3-1. Summary of Raw Water Quality Data for the Louis Stralla WTP Constituent Units Range Average Median 95th Percentile Turbidity NTU 1.5 – 12.2 3.9 3.1 9.9 Total Coliform MPN/ <1 - >2420 855 388 2419 100 mL E. coli MPN/ <1 – 40.4 2.2 1 14.9 100 mL Total Organic mg/L 3.4 – 6.1 4.7 4.8 5.7 Carbon
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SELECTED CONSTITUENT REVIEW
This section contains a general discussion of selected water quality constituents and the reasons why they were selected for further evaluation. The constituents selected for further review in this section include turbidity, total coliform, Escherichia coli (E. coli), total organic carbon (TOC), and other detectable constituents. The constituents’ general characteristics, seasonal and historical trends, and significance with respect to existing regulations are presented, along with data analysis and review. Additional evaluation of these constituents, with respect to treated water quality and regulatory compliance, is presented in Section 5.
The constituents selected for further review were selected based on several criteria including; existing regulatory standards, critical operational evaluation parameters, and relevance to significant potential contaminating activities. These items are discussed in the background section for each constituent. Table 3-2 shows the relationship between potential contaminating activities and water quality constituents.
Table 3-2. Relationship Between Potential Contaminating Activities and Water Quality Septic Unauthorized Vineyards Spills Fires Stormwater Systems Activities and Wineries Turbidity Microbial Constituents TOC
Turbidity
General Characteristics and Background
Turbidity is the measurement of light scatter in water and provides a measure of the degradation of clarity in water. Clarity is typically degraded by suspended colloids and fine suspended solids such as clay, organic particulates, and microorganisms such as Giardia and Cryptosporidium, if present. Turbidity is measured to evaluate the efficiency of the treatment process at removing these particles and also to comply with regulatory requirements.
Turbidity was selected for further evaluation since most utilities, including the City, optimize pretreatment processes to maximize turbidity removal in order to reduce the potential for pathogens, such as Giardia and Cryptosporidium, in treated drinking water. Turbidity is monitored throughout the water treatment plant to ensure that particles are removed. Turbidity has been assumed to be an indicator organism for the presence of Giardia and Cryptosporidium. However, turbidity alone may be a poor predictor of microbiological quality.
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Current drinking water regulations require that the combined filtered effluent be less than 0.3 nephelometric turbidity units (NTU) in 95 percent of monthly measurements and that the turbidity never exceed 1 NTU. Continuous turbidity monitoring for individual filters is required. Turbidity has also been indirectly regulated in drinking water as part of the Filter Backwash Rule. This rule requires that recycled waste streams return to the plant headworks upstream of all chemical feed systems and recommends return at a controlled, small percentage of total flow (less than 10 percent) to ensure that chemical feed is adjusted for blended water quality, including potential increases in turbidity caused by recycle streams.
High turbidity levels in surface water sources, such as creeks and lakes, are typically the result of erosion and sediment transport during precipitation and high flow events, and are undesirable because high turbidity can mask the presence of harmful particulates. The principal source of turbidity is general watershed runoff, and can also be contributed by other potential contaminating activities such as fires, storm water, spills, and wastewater. It is common for turbidities to vary seasonally as a result of precipitation and flow. It has also been found that the presence of suspended matter can interfere with disinfection of microorganisms.
Evaluation
Turbidity has been selected for evaluation not only because it is a regulated constituent, but also because it is commonly used as an indicator of general water quality and overall plant performance. The minimum, maximum, average, median, and 95th percentile has been summarized for the plant influent at the Louis Stralla WTP in Table 3-1. Figure 3-1 is a timeseries plot for raw water turbidity from January 2009 through December 2013 for the Louis Stralla WTP. Precipitation measured at the Bell Canyon Reservoir is also plotted with the raw water turbidities. It should be noted that the raw water turbidities are a monthly average of peak daily grab samples.
As shown in Figure 3-1, turbidity peaks are correlated to wet weather events during the winter months from December through March. It is interesting to note that for the five year reporting period, the highest monthly turbidity occurred either in the months of February or March for four years out of the five year reporting period.
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Figure 3-1. Plant Influent Peak Daily Turbidity and Precipitation for the Louis Stralla WTP, 2009 – 2013
Summary of Results for Turbidity
The Louis Stralla WTP has low levels of raw water turbidity, with average values less than 4 NTU. Most turbidity peaks generally occur during the wet season, between December and March. The highest monthly turbidities occurred in the months of February or March for four years out of the five year reporting period.
Microbiological Constituents
General Characteristics and Background
The major microbiological constituents of concern include total coliform, E. coli, Giardia lamblia, and Cryptosporidium parvum. Generally speaking, pathogenic organisms carried by mammalian species may be infectious to humans although this depends on the species of micrororganism. Pathogens infecting other types of animals, such as birds and reptiles, are usually not infectious to humans. However, some types of
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 3-4 2014 UPDATE – FINAL REPORT SECTION 3 – BELL CANYON RESERVOIR WATER QUALITY REVIEW animals, such as birds, may be vectors for human pathogens. Each of these constituents was identified for further evaluation because they are currently regulated. The presence of the constituents in the raw water governs the overall treatment requirements for the water treatment plants.
Coliform and E. coli have been used to indicate the potential presence of pathogenic microorganisms in source waters. Although coliform levels have not been shown to correlate well with pathogenic microorganisms, they continue to be used as indicators due to the lack of affordable and reliable direct analytical methods for detecting pathogens. The United States Environmental Protection Agency (USEPA) has determined that the most practical surrogate for protozoa at this time is E. coli, as required under the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). Potential sources of coliform bacteria include general watershed runoff, agricultural drainage, recreation, wastewater, urban runoff, and animal populations. Coliform levels in treated water are currently regulated directly through the Total Coliform Rule, to ensure the effectiveness of the disinfection process throughout the distribution system.
Giardia lamblia is a species of the protozoa genus Giardia that infects humans and can cause the gastrointestinal disease giardiasis. Giardia is found in the environment as a cyst from the feces of humans and animals; both wild and domestic animals may be hosts. Sources close to waterbodies have the most potential to introduce viable cysts to the source water. Cysts may be destroyed naturally in the environment by desiccation and/or heat. The cysts are effectively inactivated using chlorine disinfection. The detectability of Giardia has been greatly improved with USEPA Method 1623, which is better able to establish concentrations, but still does not determine viability. Giardia may be carried in urban runoff and wastewater sources or may be contributed directly as a result of body-contact recreation or animal defecation.
Giardia lamblia is currently regulated by the Surface Water Treatment Rule (SWTR), the Interim Enhanced Surface Water Treatment Rule (IESWTR), and the Long Term 1 ESWTR (LT1ESWTR). Surface water supplies must provide for 3-log reduction of Giardia through physical removal and chemical inactivation. Additional reduction may be required for impaired water supplies. The USEPA provided guidance with the SWTR that indicated additional reduction would be appropriate if measured Giardia levels in the source water were greater than 0.01 cysts per liter. However, in the 1980’s there was no practical means to measure Giardia, therefore the CDPH prepared guidance under the SWTR that indicated that 3-log reduction would likely be appropriate when monthly median levels of total coliform in the raw water were less than 1,000 most probable number per 100 milliliter (MPN/100 mL). In recent years CDPH has allowed for the substitution of fecal coliform or E. coli levels in raw water since they are more specific indicators.
Cryptosporidium parvum is a species of the protozoa genus Cryptosporidium that infects humans and can cause the gastrointestinal disease cryptosporidiosis. Cryptosporidium is found in the environment as an oocyst principally from the feces of
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 3-5 2014 UPDATE – FINAL REPORT SECTION 3 – BELL CANYON RESERVOIR WATER QUALITY REVIEW domestic animals, although both wild and domestic animals are known to be hosts. Like Giardia, Cryptosporidium oocysts may be destroyed naturally in the environment by desiccation and/or heat. Once in the source water, however, viable oocysts are very resistant to traditional chemical inactivation using chlorine. Stronger disinfectants such as ozone or ultraviolet (UV) light are required to inactivate these pathogens. The detectability of Cryptosporidium has been greatly improved with USEPA Methods 1622 and 1623, which are able to establish truer concentrations, but still do not determine viability. Cryptosporidium may be carried in urban runoff and wastewater sources or may be contributed directly as a result of body-contact recreation or animal defecation.
Cryptosporidium is currently regulated through the IESWTR and the LT1ESWTR, which require 2-log reduction, and the LT2ESWTR which potentially requires additional log action based on source water monitoring results for either E. coli or Cryptosporidium, depending on system size. Under the IESWTR and LT1ESWTR well-operated conventional and direct treatment plants are granted a 2-log removal credit for Cryptosporidium if they meet all treated water turbidity standards. The LT2ESWTR further regulates Cryptosporidium and requires additional action (treatment or protection) if the source water quality is determined to be impaired based on direct E. coli or Cryptosporidium monitoring of the source. Small systems with a population less than 10,000 are to first monitor for E. coli bi-weekly for one year. If the average value is greater than 10 MPN/100 mL for a lake source, then Cryptosporidium must be monitored monthly for two years. If the Cryptosporidium running annual average levels are greater than 0.075 oocysts per liter then additional action must be achieved based on bin classification of the source.
The CDPH also developed the Cryptosporidium Action Plan (CAP) in the mid-1990’s to address Cryptosporidium while federal regulations were being formed. The CAP identified recommended turbidity limits for settled water, treated water and recycled water in lieu of treated water Cryptosporidium levels. The CAP was developed to help utilities optimize treatment processes to ensure maximum removal of Cryptosporidium oocysts and reduce the risk of waterborne illness. This plan was intended for utilities with over 1,000 service connections.
Evaluation for Total Coliform and E. coli
The City monitors raw water for total coliform and E. coli on a monthly basis for the Bell Canyon Reservoir source at the Louis Stralla WTP intake. Monthly monitoring data for total coliform and E. coli were available for evaluation from January 2009 through December 2013. Figure 3-2 provides a timeseries plot of the available total coliform data during the study period. Figure 3-3 provides a timeseries plot of the available E. coli data during the study period.
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Figure 3-2. Total Coliform for Bell Canyon Reservoir, 2009 - 2013
3000
2500
2000
1500
1000 Totalcoliform, MPN/100mL
500
0
7/1/09
7/15/09
5/2/2009 6/9/2010 2/9/2011 8/10/201 5/9/2012 5/8/2013
6/22/2011 1/28/2009 2/26/2013 3/11/2009 4/22/2009 2/10/2010 4/14/2010 8/11/2010 12/8/2010 4/13/2011 11/9/2011 1/10/2012 3/14/2012 7/11/2012 9/12/2012 1/10/2013 3/13/2013 7/11/2013 9/11/2013
10/13/2010 11/14/2012 11/13/2013 12/10/2009
There were many months where total coliform levels were greater than 2,420 MPN/100mL, which is the maximum detectable concentration for the laboratory. High values tend to occur in March and May, although occasionally in October and November. High total coliform values occur during months of heavy precipitation, but can also occur during months of no precipitation. Although the cause of high total coliform is undetermined, it may be related to algal blooms occurring in the spring and fall.
E. coli data show generally low levels, with no seasonal trends evident. The highest E. coli measurement was 40.4 MPN/100mL which occurred in August 2013. The current permit specifies that in the event the E. coli is greater than 1,000 MPN/mL, an additional log removal of Giardia is required. Since 100 percent of the E. coli samples were less than 1,000 MPN/mL, no additional log removal is required. Therefore, E. coli data continue to support 3/4-log treatment for Giardia/viruses for all source water quality conditions during the study period.
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Figure 3-3. E. coli for Bell Canyon Reservoir, 2009 - 2013 45
40
35
30
25
20 E. coli, MPN/100mLcoli, E. 15
10
5
0
7/8/09
4/8/2009 5/7/2009 6/3/2009 9/8/2010 3/9/2011 2/8/2012 8/8/2012 8/7/2013
6/12/2013 1/14/2009 2/11/2009 3/25/2009 1/13/2010 3/10/2010 5/12/2010 7/15/2010 1/12/2011 5/11/2011 7/13/2011 4/11/2012 6/13/2012 2/13/2013 4/10/2013 10/9/2013
12/12/2012 11/10/2010 10/12/2011 12/14/2011 10/10/2012 12/12/2013 11/13/2009
Under the LT2ESWTR, the USEPA allows surrogate monitoring for small water systems to minimize the cost impact. The rule requires bi-weekly E. coli monitoring for one year. If the annual mean of those samples is greater than 10 MPN/100 mL (for a lake source) then the system is considered to be potentially at risk for microbial contamination and must conduct source water monitoring for Cryptosporidium. As a Schedule 4 system, the City conducted biweekly E. coli monitoring from October 2008 to September 2009 for LT2ESWTR. The average for this dataset was 1.98 MPN/100mL, well below the risk threshold for small systems under LT2ESWTR. In 2013, the City received an email from CDPH indicating that the Louis Stralla WTP was classified as Bin 1.
Summary of Results for Total Coliform and E. coli
E. coli levels are much lower than total coliform levels in the Bell Canyon Reservoir. Peaks in total coliform may be related to high precipitation events and/or algal blooms. E. coli data continue to support 3/4-log treatment for Giardia/viruses for all source water quality conditions during the study period. The Louis Stralla WTP was classified as Bin 1 by the CDPH.
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Disinfection By-Product Precursors (Total Organic Carbon)
General Characteristics and Background
Disinfection By-Products (DBPs) are formed when disinfectants added to water react with naturally occurring organic matter or other constituents, such as bromide. Since Bell Canyon Reservoir does not have detectable levels of bromide, TOC is the key precursor for DBPs. The most common DBPs are total trihalomethanes (TTHMs), which are suspected carcinogens. Other DBPs, including haloacetic acids (HAA5), are suspected mutagens and teratogens. Potential sources of these organic precursors are plant matter, animal matter, and soil, which can be contributed by general watershed runoff, urban runoff, agricultural runoff, algal blooms, recreation, grazing, and wastewater.
The Stage 1 Disinfectants/Disinfection Byproduct (D/DBP) Rule requires varying levels of TOC removal if the source water TOC concentrations exceed 2 milligrams per liter (mg/L) and a utility uses conventional filtration. TOC was a selected constituent for further evaluation due to its importance in the formation of DBPs and also as a general indicator of organic contamination in water.
Evaluation
The Bell Canyon Reservoir source was monitored monthly for TOC from January 2009 through December 2013. Figure 3-4 shows the monthly raw water TOC data for the Bell Canyon Reservoir source. All raw water samples had TOC levels greater than 2 mg/L. TOC for the Louis Stralla WTP plant influent averaged 4.7 mg/L. Similar to turbidity, the peak TOC values appear to be associated with high precipitation periods.
Summary of Results for Total Organic Carbon
The TOC data for the Bell Canyon source is always above 2 mg/L. The average TOC level over the reporting period was 4.7 mg/L. Similar to turbidity, increases in TOC appears to be correlated with high precipitation. (The highest monthly TOC levels occurred in the months of February or March for three years out of the five year reporting period.)
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Figure 3-4. Monthly TOC and Precipitation at the Louis Stralla WTP, 2009 - 2013
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Detectable Title 22 Constituents of Interest
A review of the Consumer Confidence Reports (CCRs) was conducted to identify detectable constituents of interest in the source water. As shown in Table 3-3, iron and manganese are consistently detected in the Bell Canyon Reservoir source water, with levels exceeding the secondary MCLs. Although secondary MCLs were exceeded in the source water, there were no primary or secondary MCL violations in the treated water over the reporting period.
Table 3-3. Manganese and Iron Levels in Bell Canyon Reservoir, 2009-2013
Mn Range, Exceed Fe Range, Exceed ppb Secondary ppb Secondary MCL MCL of 50 of 300 ppb? ppb? 2009 4-105 Yes, 5 times 19-350 Yes, 1 time CCR 2010 4 - 102 Yes, 4 times 46-370 Yes, 1 time CCR 2011 24 - 91 Yes, 17 times 14-530 Yes, four times CCR 2012 15 - 130 Yes, 16 times 76-960 Yes, seven times CCR
Manganese and iron are naturally-occurring minerals in the watershed, and are consistently detected in the source water. As shown in Table 3-3, manganese and iron were detected more frequently above their respective secondary MCLs in 2011 and 2012, which may have been due to a malfunctioning mid intake valve, which was partially stuck open from February 2009 to October 2012.
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This section contains an evaluation of the six potential contaminant sources (PCS) selected for review for the current Update: (1) source water spills, (2) wineries/vineyards, (3) unauthorized activity, (4) storm water, (5) septic systems, and (6) fires. These PCSs were selected based on their presence in the watershed and their potential to impact Bell Canyon Reservoir.
SPILLS
Background
A hazardous material spill or leak into a surface water body could occur as the result of a vehicular traffic accident, pipeline leak or spill, wastewater treatment plant spill, or other incident. In the event of a leak or spill, timely notification is critical to ensure that the water treatment plant operators are provided with sufficient time and information to best respond to potential treatment concerns. As the Bell Canyon watershed does not include wastewater treatment plants or sewer collection systems, wastewater spills would originate only from malfunctioning or compromised septic systems. Information on septic systems will be provided later in this section.
Seasonal Patterns
There are no seasonal patterns as to when spills may occur due to the various causes of spills.
Related Constituents
The most common spills are related to oil and petroleum products or sewage. Therefore, typical constituents of concern range from volatile organic compounds (VOCs) and hydrocarbons to microbial constituents (i.e. viruses, pathogens, Giardia, Cryptosporidium). However, hazardous materials emergencies can involve a virtually infinite number of chemicals or chemical combinations.
Occurrence in Watershed
The main transportation route through the watershed is White Cottage Road. Deer Park Road borders the southeast portion of the watershed, but is technically outside. Spill information was queried from the Office of Emergency Services (OES) Response Information Management System (RIMS) archived database and the State Water Resources Control Board’s (SWRCB) California Integrated Water Quality System (CIWQS) database on sanitary system overflows (SSOs).
The OES’ RIMS database did not contain any spills in the watershed from 2009 through 2013 and the SWRCB’s CIWQS database did not contain any SSOs from private laterals.
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Related Water Quality Issues and Data Review
As there were no spills in the watershed, it is not necessary to review source water quality from Bell Canyon Reservoir to determine any water quality impacts.
Regulation and Management
When a hazardous materials spill or leak of a reportable quantity occurs, notification to an emergency response agency is required by state and federal law. A sewage spill is required to be reported if 1,000 gallons or more are released. An oil or petroleum product spill is required to be reported if 42 gallons or more are released. Any other hazardous materials spill is required to be reported if there is a reasonable belief that the release poses a significant present or potential hazard to human health and safety, property, or the environment. When a hazardous materials spill or leak occurs, it is the owner’s or operator’s responsibility to notify the local designated emergency response agency, which is called the Certified Unified Program Agency (CUPA), as well as the OES. Depending on the type of spill and where it occurred, other agencies such as the U.S. Forest Service, the U.S. Fish and Wildlife Service, the California Department of Fish and Game, and the San Francisco Bay Regional Water Quality Control Board (Regional Board) may be involved. An incident report would then be sent to OES.
California Emergency Management Agency
OES developed the RIMS as part of the development of the State’s Standardized Emergency Management System (SEMS). The purpose of RIMS is to provide a single point for tracking the status and progress of hazardous materials spills statewide. Only registered users can input data into RIMS, but anyone can access the website to review current or archived OES cases.
The archived cases, including those from 1993 through 2013, were accessed at: http://www.calema.ca.gov/HazardousMaterials/Pages/Historical-HazMat-Spill- Notifications.aspx
Recommended Source Water Protection Activities
There are no recommended source water protection activities at this time.
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WINERIES/VINEYARDS
Background
Winery wastewater comes primarily from grape-crush, barrel-cleaning, and bottling operations. Some wineries send their process wastewater to a septic system, while others send their process wastewater to wastewater ponds. Larger wineries have on- site treatment systems. Generally, treated winery wastewater from on-site ponds or treatment systems is used as irrigation water to designated vineyards, pastures, or landscape irrigation areas through spray or drip irrigation.
If a winery sends their process wastewater to a septic system, then domestic wastewater must be sent to a separate septic system. A combined septic system receiving both process wastewater and domestic wastewater is not allowed. However, a combined leach field is allowed.
Other concerns with wineries are storm water runoff, sediment discharges due to erosion, and pesticide use.
Seasonal Patterns
Although the harvest for wine grapes is usually August through early November, the type of grapes and weather can alter the harvest period. Other aspects of the operations such as blending, racking, and bottling occur other times of the year. Since each winery is different, there are no easily identifiable seasonal patterns associated with winery operations.
Related Constituents
Erosion from vineyards may contribute turbidity and suspended solids to Bell Canyon Reservoir. Storm water runoff from wineries may be a source of turbidity, salinity, and total organic carbon. Vineyards may also be a source of pesticides, depending on the amounts used.
Winery wastewater generally does not contain pesticides, chemicals, or fecal matter. One of the key concerns with winery wastewater is natural sugar in the grapes which dissolves easily in the water and is measured as Biochemical Oxygen Demand (BOD).
Occurrence in Watershed
In order to enumerate the number of wineries within the study watershed, the Napa County Environmental Health Division was contacted. As shown in Table 4-1 and Appendix C, one winery is pending approval, two are approved to begin production, and eight are actively producing.
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Table 4-1. Wineries and Vineyards in Bell Canyon Reservoir Watershed as of 2013 Facility Name Address Status Ladera 150 White Cottage Road, Angwin, Producing CA 94508 Bravante Vineyards 300 Stone Ridge Road, Angwin, CA Producing 94508 Livingston Moffett Winery 340 West Lane Angwin, CA 94508 Producing (Vineyard only) Arkenstone Vineyards 335 West Lane Angwin, CA 94508 Producing Neal Family Vineyards 716 Liparita Angwin, CA 94508 Producing Burgess Cellars 1108 Deer Park Road, St Helena CA Producing 94574 Viader 1120 Deer Park Road, Deer Park Producing 94576 O’Shaughnessy P.O. Box 923 Angwin, CA 94508 Producing Cimarossa P.O. Box 573 Angwin, CA 94508 Approved Lail Vineyards P.O. Box 249 Rutherford, CA 94573 Approved Diogenes Ridge Winery Not available Pending
Appendix C shows that the total vineyard acreage in the watershed is 262 acres. The largest single parcel dedicated to vineyards is 29.99 acres owned by Ladera. The two other large parcels are 26.77 acres owned by Burgess and 21.23 acres owned by Viader. The parcels owned by Viader and Burgess are of most concern due to their proximity to the Bell Canyon Reservoir and they appear to be on a steep grade, as shown in Figure 4-1.
Figure 4-1. Bell Canyon Reservoir, looking from Burgess Cellars Vineyard
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Wineries and vineyards may be required to have a permit or plan from Napa County under the areas of sewage system monitoring, erosion control and storm water. Each of the respective departments in Napa County were contacted for information, and information on sewage monitoring permits and erosion control plans will be discussed below. Information on stormwater pollution prevention plans and inspections will be discussed in the Storm Water Section. Table 4-2 is a summary of which facilities were required to have a sewage system monitoring permit, erosion control plan, or stormwater pollution prevention plan.
Table 4-2. Wineries/Vineyards in Bell Canyon Reservoir Watershed – Summary of Permits and Plan Regulated by Napa County
Facility Name Sewage System Erosion Stormwater Pollution Monitoring Control Plan Prevention Plan Permit Ladera X X X Bravante Vineyards X X No, County will contact Livingston Moffett Winery Vineyard only No Vineyard only Arkenstone Vineyards X X, only portions X of vineyard Neal Family Vineyards X No X Burgess Cellars No, likely No, has covered crush pad predated requirement Viader X No, has covered crush pad O’Shaughnessy X X, active No, has covered crush pad Cimarossa Unable to Unable to determine determine Lail Vineyards Unable to Unable to determine determine Diogenes Ridge Winery X, active Unable to determine
Sewage System Monitoring Permit – County of Napa
Ladera Winery, Neal Family Vineyards, Bravante Vineyards, O’Shaughnessy, and Arkenstone Winery have sewage system monitoring permits issued by the Napa County, Planning, Building and Environmental Services. A permit is needed if the winery processes more than 1,500 gallons of process water a day, or the septic system in place is an engineered system. Wineries operating prior to 2000 are not required to have this permit.
According to Napa County, some of the permit requirements are (Personal Communication, Kim Withrow, County of Napa, January 2014). :
A minimum of six groundwater monitoring wells must be installed to detect offsite movement of treated process water. An approved service provider must inspect the sewage system twice a year. The inspection should include monitoring groundwater levels in the monitoring wells, checking flow rates, and checking filters.
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The County inspects these systems every other year. Additional information was requested and obtained from the County regarding system type, flow rate, and inspection results, as shown in Table 4-3. Overall, the County did not identify any specific issues related to septic system impacts or failures to impact Bell Canyon Reservoir.
Table 4-3. Winery/Vineyards Facilities in Bell Canyon Reservoir Watershed with Sewage System Monitoring Permits
Facility Permit System Flow Rate Results of Name Date Type Last Inspection Ladera Winery 2002 Pressure 3,750 Alarm float Distribution gallons/day not System functioning due to electrical problem Neal Family 2000 Pressure 1,433 No Vineyard Distribution gallons/day violations System Arkenstone 2007 Standard 600 No Winery system for gallons/day for violations sanitary sanitary waste; waste; 1,600 Pressure gallons/day for Distribution process water System for Process Waste Bravante 2005 Pressure 725 Information Vineyards Distribution gallons/day not System available O’Shaughnessy 2001 Pressure 880 Roots and Distribution gallons/day groundwater System intrusion at septic tanks Source: Napa County Building, Planning, and Environmental Services
Erosion Control Plan – County of Napa
Vineyards located on slopes greater than five percent are required by Napa County to submit an Erosion Control Plan. According to Napa County, annual inspections prior to the rainy season are conducted by the Napa County Resource Conservation District (RCD) if the plan is “active” (Personal Communication, Brian Bordona, County of Napa, February 2014). The purpose of the inspection is to check if the erosion control plan is being implemented properly. When all of the best management practices as specified in the erosion control plan are implemented, the plan is finalized and annual inspections are not conducted anymore. However, five percent of all finalized plans are spot checked every year at random. If there are any violations, the RCD reports the findings
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Due to the steepness of the vineyards owned by Viader and Burgess Cellars, and proximity to Bell Canyon Reservoir, it was inquired of the County if there were any erosion issues with these particular parcels. Overall, the County did not identify any specific issues related to erosion to impact Bell Canyon Reservoir.
Crops and Pesticide/Herbicide Use
The Napa County Crop Report produced by the Office of the Agricultural Commissioner reports that the highest fruit and nut crop by acreage is wine grapes. In 2012, the total wine grape acreage in Napa County was 43,581. After wine grapes, olives have the next highest acreage, at 191 acres in 2012. Pasture and rangeland also had a high acreage in Napa County with 95,000 acres in 2012. However, this field crop is not pertinent to the Bell Canyon Reservoir watershed.
The major pesticides and herbicides used on wine grapes in Napa County in 2012 are shown in Table 4-4. Sulfur, a fungicide used to combat powdery mildew, is applied in much greater quantities than any other pesticide or herbicide. Sulfur is oxidized by bacteria and becomes sulfate. Glyphosate is an herbicide used to control weeds.
Table 4-4. Pesticide and Herbicide Usage in Napa County on Wine Grapes in 2012
Pesticide/Herbicide Napa County Usage, lbs. Sulfur 921,812 Mineral Oil 108,189 Petroleum Distillates, Refined 41,834 Glyphosate, Potassium Salt 33,495 1,3-Dichloropropene 4,332
Related Water Quality Issues and Data Review
There are no direct discharges of process wastewater from wineries. Wineries can potentially impact Bell Canyon Reservoir water quality due to accidental spills of process wastewater and due to runoff of pesticides and sediment from vineyards. According to Napa County, there have been no recent incidents where a winery significantly impacted the Bell Canyon Reservoir or its water quality.
Regulation and Management
Wineries and vineyards in Napa County are regulated by the Napa County Environmental Health Division, as an MOU was signed by Napa County and the San Francisco Bay Regional Water Quality Control Board in November 1982. The MOU
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Napa County Code of Ordinances (18.108.027 Sensitive domestic water supply drainages) specifies that the owner/operator of a public water supply system in a sensitive domestic supply drainage, such as Bell Canyon Reservoir, shall receive a copy of any erosion control plan filed in their drainage. Each notice will be given twenty- one days for a response.
If the owner/operator submits credible evidence within this time period that the delivery of sediment or other pollutants into their reservoir(s) from the drainage will be increased by more than one percent on an individual project basis or by more than ten percent on a cumulative basis, the erosion control plan shall not be approved until a public hearing on the matter has been held before the commission and a use permit has been issued.
Recommended Source Water Protection Activities
It is recommended that the City keep track of vineyard developments in the watershed by ensuring that all erosion control plans forwarded by Napa County are reviewed by the City.
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UNAUTHORIZED ACTIVITY
Background
Typical unauthorized activities that may be potential contaminant sources are illegal dumping, illegal camping and unsanctioned recreational activities. Bell Canyon Reservoir is not open to the public for recreation. There are no hiking, biking, or equestrian trails in the areas surrounding the reservoir.
Occurrence in Watershed
Unauthorized swimming occurs on occasion, but staff believes that it is occurring less compared to the previous five to ten years. Also, there is general littering of cans and plastic bags, but no illegal dumping of any hazardous materials. A concrete skateboard ramp was demolished over the reporting period. Similar to incidents reported in the 2003 and 2009 Updates, there was graffiti painted on the spillway in 2013, and spray paint containers and other paint containers left in the watershed.
The length of fencing along the road to the spillway around City property was increased in March 2003 and April 2006, where many of the unauthorized recreational users gained access to the reservoir. Extending the fence and gating access to the spillway road has reduced the use of the area by recreationists.
Although it is not an unauthorized activity, there is a shooting range owned by the City of St. Helena Police Department. According to the City’s Police Chief, the range has been in use for approximately 40 years. It is currently used by California Department of Forestry (CALFIRE), the Napa County Sheriff’s Office, and local city police departments. The facility was visited during the field survey in November 2013, and ammunition shells were observed on the ground. Figure 4-2 shows the location of the shooting range in proximity to Bell Canyon Reservoir and Figure 4-3 shows one area of the shooting range.
In October 2013, a meeting was held with the City’s Public Works Director, the City’s Police Chief, and the City’s Chief Operator. The outcome of the meeting was that the Police Chief would estimate the cost to remove the bullets and see what other agencies have done for cleanup.
Related Water Quality Issues and Data Review
As mentioned in the 2009 Watershed Sanitary Survey, a study conducted by the San Francisco Public Utilities Commission showed that contaminants such as lead and arsenic could leach from ammunition and shells.
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Figure 4-2. Shooting Range with Bell Canyon Reservoir in Background
Figure 4-3. Shooting Range in Bell Canyon Reservoir Watershed
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Regulation and Management
The City prohibits recreational use of the lake and the City property. As there are no public recreation areas in the watershed, there is no management in the watershed by state or local public recreation agencies. City operators conduct weekly inspections on the spillway.
Recommended Source Water Protection Activities
It is recommended the City continue to evaluate options to remove bullets from the City’s shooting range which could leach contaminants such as arsenic and lead.
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STORMWATER
Background
Storm water runoff from wineries may be a source of sediment, salinity, and total organic carbon.
Seasonal Patterns
Wet weather runoff is of relatively short duration and can have highly variable pollutant concentrations. Generally, the impact is the greatest immediately following a first-flush event.
Occurrence in Watershed
Municipalities are required to obtain Municipal Separate Storm Sewer Systems (MS4s) Permits which regulate storm water discharges. MS4 permits are issued by Regional Water Quality Control Boards and are usually issued to a group of co-permittees encompassing an entire metropolitan area.
On December 8, 1999, EPA promulgated regulations, known as Phase II, requiring permits for stormwater discharges from small MS4s and from construction sites disturbing between one and five acres of land. The Cities of Napa, St. Helena, the town of Yountville, and the County of Napa applied for the Phase II permit on March 10, 2003. These municipalities currently implement a stormwater program to reduce stormwater pollution.
The MS4 permit requires the discharger to develop and implement a Storm Water Management Program with the goal of reducing the discharge of pollutants to the maximum extent practicable. The six required plan components are: public education and outreach, public involvement/participation, illicit discharge detection and elimination, construction activities, post-construction storm water management, and good housekeeping for municipal operations.
Storm Water Pollution Prevention Plan – County of Napa
According to Napa County, the main elements of the storm water management plan which pertain to the Bell Canyon Reservoir watershed are inspections of vineyards and construction sites for erosion control. Information on vineyards and erosion control was discussed under Wineries/Vineyards.
Wineries may also be inspected by the County for storm water based on their Standard Industrial Classification (SIC) code. Within the Bell Canyon watershed, storm water inspections were conducted at Ladera in 2011, Neal Family Vineyards in 2013, and Arkenstone Vineyards in 2012.
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According to Napa County, Viader, O’Shaughnessy and Burgess Cellars are not inspected for storm water as they have a covered crush pad. Bravante Vineyards was not listed in the County’s database and it was indicated that the County will send them a letter to determine their permit status (Email communication, Doug Calhoun, County of Napa, January 2014).
General Industrial Storm Water Permit – State Water Resources Control Board
The State Water Resources Control Board’s Storm Water Multiple Application and Report Tracking System, (SMARTS) database includes wineries which were required to obtain a General Industrial Storm Water Permit. The only winery in the watershed which holds this General Industrial Storm Water Permit is Arkenstone Vineyards.
As required by the General Industrial Storm Water Permit, Arkenstone Vineyards must submit an annual report every year. Three annual reports (2010-2011, 2011-2012, and 2012-2013) were reviewed. The annual report verifies that the facility is: sampling for two storm events every year (and providing water quality results) conducting a monthly visual inspection for storm water discharges occurring on- site. inspecting potential pollutant sources and industrial activities reviewing its storm water pollution prevention plan to assure that BMPs are in place.
Related Water Quality Issues and Data Review
As required by the General Industrial Activities Storm Water Permit, the Arkenstone Vineyards is required to sample two storm events per year. Table 4-5 summarizes three storm events on December 27, 2010, March 16, 2012 and December 3, 2012 which were sampled for total suspended solids, pH, TOC, electrical conductivity, and oil and grease.
Table 4-5. Storm Water Sampling Results from Arkenstone Vineyards, 2010-2012
Constituent 12/27/10 3/16/12 12/3/12 Total Suspended Solids, ND ND 55 mg/L pH 7.4 7.2 2.3 Total Organic Carbon, mg/L 2.5 1.5 8.6 Electrical Conductivity, 190 58 3,000 umhos/cm Oil and Grease, mg/L ND ND ND
Based on these limited analyses, storm water discharges from wineries and vineyards can be a source of turbidity, TOC and salinity.
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Regulation and Management
State Water Resources Control Board
The General Industrial Permit is a NPDES permit that regulates discharges associated with 10 broad categories of industrial activities. The General Industrial Permit requires the implementation of management measures that will achieve the performance standard of best available technology economically achievable (BAT) and best conventional pollutant control technology (BCT). The General Industrial Permit also requires the development of a Storm Water Pollution Prevention Plan (SWPPP) and a monitoring plan. Through the SWPPP, sources of pollutants are identified, and the means to manage the sources to reduce stormwater pollution are described. The General Industrial Permit requires that an annual report be submitted each July 1.
The SWRCB is currently updating the Industrial General Permit (SWRCB Order No, 97- 03-DWQ as it is expired. In July 2013, the SWRCB released the 2013 Draft NPDES Industrial General Permit. The public comment period ended in September 2013, and the final draft is scheduled for early 2014.
County of Napa Planning, Building and Environmental Services
As stated earlier, wineries are inspected by the County for stormwater compliance. They are inspected every three years. A typical inspection consists of checking if all hazardous materials stored outside are kept in a manner to prevent contact with stormwater runoff, checking if all repair/maintenance/processing areas are enclosed with drains going to sewer system, checking if outdoors washwater is collected and disposed of properly, checking if all drains are connected to sewer system, and checking if parking areas and equipment storage areas are free of visible pollutants. A review of the most recent inspection reports for Ladera, Neal Family Vineyards and Arkenstone showed that the facilities were in compliance for stormwater.
Recommended Source Water Protection Activities
There are no recommended source water protection activities at this time.
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SEPTIC SYSTEMS
Background
Failing or poorly sited septic systems, leaking sewer lines, and wastewater discharges can be potential sources of fecal indicator bacteria and human pathogens.
Related Constituents
Septic tank effluent typically contains high concentrations of total dissolved solids, chlorides, phosphates, nitrates, bacteria, and viruses.
Occurrence in Watershed
The Napa County Department of Planning, Building, and Environmental Services, Environmental Health Division was contacted to estimate the number of septic systems in the area. They indicated that they do not keep records to estimate this type of information. Based on the research conducted by Archibald Consulting for the 2003 Update, there were 100 land parcels in the watershed. The Napa County Department of Planning, Building and Environmental Services agreed that an estimate of 100 septic systems in the watershed would be an estimate on the high side as some of the parcels are vineyards or undeveloped (Personal Communication, John Kara, County of Napa, November 2013).
The Napa County Environmental Department of Planning, Building, and Environmental Services were also contacted for sewage complaints or sewage spills. Napa County has a database of septic system failures which dates back to July 1, 2009. There were two reports of septic system failure in the watershed as shown in Table 4-6. The volume of sewage released was not reported for either failure. However, the sewage did not reach any surface waters (Personal Communication, John Kara, County of Napa, November 2013).
Table 4-6. Septic System Violations in Bell Canyon Reservoir Watershed, 2009-2012
Notification Address Community Description Received 2/9/2010 430 Sky Oaks Angwin Sewage surfaced due to a broken pipe and system has been repaired. 4/2/2012 226 Mariposa Angwin Sewage surfaced due to an unknown cause. The release was stopped and the house is now vacant.
Source: Napa County Environmental Dept. of Planning, Building, and Environmental Services
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Other Facilities
The San Francisco Bay Regional Water Quality Control Board was contacted to verify whether or not there are facilities which hold permits to either discharge to land (waste discharge requirements) or to waters of the U.S. (National Pollutant Discharge Elimination System) within the watershed. The Regional Board confirmed that there are no facilities which have individual NPDES permits in Angwin or St. Helena. There were four sites with waste discharge requirements in Angwin, but these were for two dredge/fill sites and two wastewater treatment plants (Angwin Village WWTP and Pacific Union College WWTP) located outside of the watershed. There were 26 facilities in the City of St. Helena with waste discharge requirements, but the only facility located in the watershed is the Louis Stralla Water Treatment Plant. There are no wastewater treatment plants in the watershed that discharge to either water or land.
Related Water Quality Issues and Data Review
As there were no septic system failures that reached a surface water in the watershed, it is not necessary to review source water quality from Bell Canyon Reservoir to determine any water quality impacts.
Regulation and Management
Residential Septic Systems
The County inspects non-standard systems on a regular basis, and inspects standard systems on a complaint basis.
Source Water Protection Activities
There are no recommended source water protection activities at this time.
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FIRES
Background
The aftermath of a wildfire or prescribed burn can alter source water quality. In general, the load of dissolved substances to streams will increase following a wildfire due to increased runoff. Increased runoff can occur following a fire because the formation of a hydrophobic organic layer in the soil increases the water repellency of soils (DeBano, 2000). A 2004 USGS study concluded that measurable effects of fires on runoff water quality are most likely to occur if the fire was severe enough to burn large amounts of organic matter, if windy conditions were present during the fire, if heavy rain occurred following the fire, and if the fire occurred in a watershed with steep slopes and soils with little cation-exchange capacity (USGS, 2004).
Seasonal Patterns
Wildfire season in Napa County spans the months after the last spring rains until the first fall or winter rains occur. The months of August, September, and October have the greatest potential for wildland fires as vegetation dries out and humidity levels fall.
Related Constituents
The magnitude of the effects of fire on water quality is dependent on how fire characteristics (frequency, intensity, duration, and spatial extent of burning) interact with watershed characteristics (weather, slope, soil type, geology, land use, timing of regrowth of vegetation, and burn history). This interaction is complex and highly variable so that even fires in the same watershed can burn with different characteristics and produce variable effects on water quality. Typically, stormwater runoff from burned forested areas contains high concentrations of phosphorus, nitrogen, dissolved organic carbon, sediment, and metals such as mercury, lead, and arsenic.
Occurrence in Watershed
According to the historical fire database on the CALFIRE website, there were no fires which occurred within the study watershed since 2009. Fires smaller than 300 acres were not included in the database.
CALFIRE has mapped fire hazard severity levels in Napa County (http://frap.fire.ca.gov/webdata/maps/napa/fhszl06_1_map.28.pdf). Fire hazard is a measure of the likelihood of an area burning and how it burns (e.g. intensity, speed, embers produced). The Bell Canyon watershed is characterized as Very High Fire Hazard Severity Zone.
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Related Water Quality Issues and Data Review
After a fire has occurred, the natural vegetation on hillsides is denuded. Additionally, a fire can cause the soils to become hydrophobic. Therefore, increased erosion of soils and associated discharge is expected to occur during the first rains immediately following a fire due to water repellent soils and reduced surface cover.
Regulation and Management
The County of Napa contracts with the CALFIRE for fire protection services as the Napa County Fire Department. The County also contracts with the City for fire protection services for specified unincorporated areas adjoining the City.
The use of approved long-term retardants in wildland fire suppression is standard in fire management and planning. The retardants are most often delivered in fixed or rotor- wing aircraft. Current qualified products and approved uses are listed on the U.S. Forest Service Wildland Fire Chemical Systems website (http://www.fs.fed.us/rm/fire). According to the U.S. Forest Service, the fire retardant commonly used is Phos-Check. The use of fire retardants can impact water quality if chemicals are accidentally dropped into a water body, or if heavy rains occur before the product has had time to naturally degrade.
The National Interagency Fire Center has developed Interagency Standards for Fire and Fire Aviation Operations which are annually revised. The Interagency Standards for Fire and Fire Aviation Operations states, references, or supplements policy for the U.S. Bureau of Land Management, the U.S. Forest Service, the U.S. Fish and Wildlife Service, and the National Park Service. Regarding the use of fire retardants, the Aerial Application Guidelines are to “avoid aerial or ground application of retardant or foam within 300 feet of waterways.” (http://www.fire.blm.gov/Standards/redbook.htm)
Recommended Source Water Protection Activities
No source water protection activities recommended at this time.
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The purpose of this section is to evaluate the Louis Stralla Water Treatment Plant (WTP) for its compliance with existing drinking water regulations.
For assistance with abbreviations and acronyms, the reader is referred to the List of Abbreviations at the front of the report.
Highlights of Selected Existing Drinking Water Regulations
NIPDWR and Phase I, II, and V Regulations. Set MCLs for many inorganic chemicals, synthetic organic compounds (SOCs), and volatile organic compounds (VOCs). Surface Water Treatment Rule (SWTR). Sets minimum 3/4-log reduction requirement for Giardia and viruses, respectively. Set turbidity requirements, which have since been tightened by the Interim Enhanced Surface Water Treatment Rule. Interim Enhanced SWTR (IESWTR) and Filter Backwash Rule. Sets minimum 2-log reduction requirement for Cryptosporidium. Requires continuous monitoring of individual filter effluents (IFE) and combined filter effluent (CFE). Tightened treated water turbidity requirements: CFE < 0.3 NTU in 95 percent of monthly measurements, and not to exceed 1 NTU. Set IFE reporting and evaluation requirements. Requires recycling of all return flows to the headworks, upstream of chemical feed. Stage 1 Disinfection/Disinfection By-Product (D/DBP) Rule. Sets a treatment technology for DBP precursor removal (enhanced coagulation) based on source water total organic carbon (TOC) levels. Varying levels of removal are required if the source water concentrations are > 2 mg/L. Sets maximum contaminant levels (MCLs) for TTHMs and HAA5 at 80/60 μg/L, respectively, in the distribution system as system-wide running annual average (RAA). Long Term 2 Enhanced SWTR. Requires Cryptosporidium, or Escherichia coli (E. coli) source water monitoring depending on system size. Source water bin classification dependent on monitoring results. If average Cryptosporidium value is > 0.075 oocysts/L, bin classification will require additional action (which could be additional log reductions or other actions, including source water protection). Also requires disinfection profiling and benchmarking if monitoring for Cryptosporidium. A second round of source water monitoring will be conducted again, six years after initial bin classification. Stage 2 D/DBP Rule. Requires compliance with distribution system MCLs for TTHM and HAA5 to be based on locational running annual average (LRAA). In Stage 2 compliance is based on LRAA of 80/60 μg/L. Initial Distribution System Evaluations were completed to identify long term routine monitoring locations. Compliance schedules will depend on system size and source type. For combined distributions systems, all systems will be on schedule of earliest system.
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LOUIS STRALLA WATER TREATMENT PLANT
System Description
The Louis Stralla WTP receives water from Bell Canyon Reservoir which receives water from Bell Creek and other small tributaries within the watershed.
Currently the average flow through the plant is 0.64 MGD in winter and 0.92 MGD in summer. The WTP began operation in 1980 and was upgraded in 1995. The plant provides complete conventional treatment including chemical addition, flash-mixing, dual train flocculation and sedimentation, multi-media rapid sand filtration, and disinfection. Additional information about the treatment process and chemicals used are described in detail in Section 2.
Water Quality Summary
Below is a discussion of each of the constituents of interest and any notable compliance issues for each constituent during the period of study.
Turbidity
The average of peak daily raw water turbidity at the Louis Stralla WTP for the period of study was 3.9 NTU, and on average the treatment process decreased this to 0.04 NTU, which equates to an average solids removal of 98.9 percent from raw to treated. The average of peak daily settled water turbidity was 1.2 NTU, with an average solids removal of 69 percent from raw to settled water over the period of study.
Figure 5-1 shows a time series plot of raw, settled and treated turbidities. It should be noted that the raw and settled water turbidities plotted are a monthly average of peak daily grab samples. The treated water turbidities are a monthly average of a daily average, based on all 4-hr samples in a 24 hour period.
A particularly challenging treatment period was in January and February 2013. Figure 5-1 shows little removal from raw to settled water during these months. Low alkalinity in the source water due to heavy rains made it difficult to optimize the alum dose, which resulted in higher than normal settled water turbidities. During this time, it was discovered that adding PAC 911 with alum in jar testing produced favorable results. However, the PAC was not utilized as the problem was resolved by the time the PAC was shipped to the Louis Stralla WTP. It is important to note that the WTP met all treated water turbidity standards during this particular time period and over the reporting period.
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Figure 5-1. Louis Stralla WTP– Raw, Settled, and Treated Water Turbidities, 2009 – 2013 100
10
1 Turbidity, Turbidity, NTU
0.1
0.01
Peak Raw Water (Monthly Average) Peak Settled Water (Monthly Average) Treated Water Filter #1 (Monthly Average)
Microbiological Constituent Review
Distribution system monitoring for coliforms as part of the Total Coliform Rule resulted in a single detection of total coliform in the distribution system reported on the 2011 and 2012 Consumer Confidence Reports during the study period. In each month with a detect, less than five percent of samples were positive and there were no fecal coliform detected. Therefore, there were no violations of the coliform maximum contaminant level (MCL).
Disinfection By-Products and Precursors
The City of St. Helena (City) monitored TOC levels in its raw water and treated water monthly between 2009 and 2013 in order to determine compliance with the TOC treatment technique of the Stage 1 D/DBP Rule. As presented in Section 3 the plant influent has an average TOC of 4.7 mg/L. Based on the plant effluent samples, the average treated water TOC level is 2.1 mg/L. Figure 5-2 presents the raw and treated TOC data. Approximately 64 percent of treated water samples were greater than 2.0 mg/L. The Louis Stralla WTP provides an average of 55 percent reduction of TOC.
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 5-3 2014 UPDATE – FINAL REPORT SECTION 5 – INTAKE EVALUATION
Figure 5-2. Louis Stralla WTP – Raw and Treated Total Organic Carbon, mg/L, 2009 – 2013
7
6
5
4
3
2 TotalOrganic Carbon,mg/L 1
0
7/14/09 1/14/09 4/14/09 1/14/10 4/14/10 7/14/10 1/14/11 4/14/11 7/14/11 1/14/12 4/14/12 7/14/12 1/14/13 4/14/13 7/14/13
10/14/09 10/14/10 10/14/11 10/14/12 10/14/13
Treated Raw TOC Water TOC
For source or treated waters with a running annual average TOC greater than 2.0 mg/L, the TOC removal ratio is required to be calculated. This is Step 1 of the Enhanced Coagulation treatment technique of the Stage 1 D/DBP Rule. TOC removal requirements are based on source water TOC and alkalinity levels, as shown in Table 5-1. Table 5-1. TOC Enhanced Coagulation Removal Requirements (Percent) Alkalinity, mg/L as CaCO3 TOC, mg/L 0 – 60 > 60 – 120 > 120 > 2.0 - 4.0 35 25 15 > 4.0 - 8.0 45 35 25 > 8.0 50 40 30
Source water average alkalinity is 27.5 mg/L at the Louis Stralla WTP. For sources with TOC between 2 mg/L and 4 mg/L and alkalinity below 60 mg/L, 35 percent TOC removal is required. For sources with TOC between 4 and 8 mg/L and alkalinity below 60 mg/L, 45 percent TOC removal is required. Table 5-2 presents the monthly TOC data and removal ratios for the Louis Stralla WTP. It can be seen that in 58 out of 60 months, the Louis Stralla WTP is complying with the Step 1 TOC removal requirements. Although the TOC removal requirements were not met in January 2009 and December
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 5-4 2014 UPDATE – FINAL REPORT SECTION 5 – INTAKE EVALUATION
2009, the running annual average for TOC removal ratio was met and the WTP is in compliance with the Step 1 TOC removal requirements.
Table 5-2. Enhanced Coagulation Removal Requirements at Louis Stralla WTP, 2009 – 2013
Date Raw Treated Raw Percent Raw Treated Required Actual Met Water Water Alkalinity Removal TOC TOC < Removal Removal Enhanced TOC TOC mg/L <2 2 mg/L Greater Coagulation? mg/L than Required Removal ? 1/14/09 4.1 2.6 25 36.6% NO NO 45% NO NO
2/11/09 3.8 2.2 29 42.1% NO NO 35% YES YES 3/11/09 5.7 2.4 27.5 57.9% NO NO 45% YES YES 4/8/09 5.6 2.6 25 53.6% NO NO 45% YES YES 5/20/09 4.3 2.1 28.5 51.2% NO NO 45% YES YES 6/10/09 4.2 2.0 23.5 52.4% NO NO 45% YES YES 7/8/09 5 2.4 37.8 52.0% NO NO 45% YES YES 8/12/09 4.7 2.3 27.5 51.1% NO NO 45% YES YES 9/9/09 5.3 2.5 30.5 52.8% NO NO 45% YES YES 10/14/09 5.9 2.7 29 54.2% NO NO 45% YES YES 11/17/09 5.2 2.8 30 46.2% NO NO 45% YES YES 12/10/09 5 2.8 33.5 44.0% NO NO 45% NO NO 1/13/10 4.8 2.2 33.5 54.2% NO NO 45% YES YES 2/10/10 5.6 2.4 21 57.1% NO NO 45% YES YES 3/10/10 5 1.9 22 62.0% NO YES 45% YES YES 4/14/10 4.9 0.5 21 89.8% NO YES 45% YES YES 5/12/10 4.4 1.8 29 59.1% NO YES 45% YES YES 6/9/10 4.1 1.9 26.5 53.7% NO YES 45% YES YES 7/15/10 5 2.6 28 48.0% NO NO 45% YES YES 8/11/10 4.1 2.1 25 48.8% NO NO 45% YES YES 9/8/10 4.5 1.9 32 57.8% NO YES 45% YES YES 10/13/10 4.5 1.9 32.5 57.8% NO YES 45% YES YES 11/10/10 4.3 1.9 29 55.8% NO YES 45% YES YES 12/8/10 4.4 1.9 29 56.8% NO YES 45% YES YES 1/12/11 4.7 1.8 24.5 61.7% NO YES 45% YES YES 2/9/11 4.7 1.8 27 61.7% NO YES 45% YES YES 3/16/11 4.7 1.7 24.5 63.8% NO YES 45% YES YES 4/13/11 3.8 1.6 23 57.9% NO YES 35% YES YES 5/11/11 4 1.9 25 52.5% NO YES 45% YES YES 6/9/11 4.6 2.2 30 52.2% NO NO 45% YES YES 7/13/11 3.6 1.7 28 52.8% NO YES 35% YES YES
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 5-5 2014 UPDATE – FINAL REPORT SECTION 5 – INTAKE EVALUATION
Date Raw Treated Raw Percent Raw Treated Required Actual Met Water Water Alkalinity Removal TOC TOC < Removal Removal Enhanced TOC TOC mg/L <2 2 mg/L Greater Coagulation? mg/L than Required Removal ? 8/10/11 4.1 1.8 30.5 56.1% NO YES 45% YES YES 9/14/11 3.8 1.8 33 52.6% NO YES 35% YES YES 10/12/11 4 1.8 29 55.0% NO YES 45% YES YES 11/9/11 3.5 1.7 32 51.4% NO YES 35% YES YES 12/14/11 4 2 22 50.0% NO NO 45% YES YES 1/11/12 3.4 1.9 28.5 44.1% NO YES 35% YES YES 2/8/12 4.9 2.1 22.5 57.1% NO NO 45% YES YES 3/14/12 5.5 2 26 63.6% NO NO 45% YES YES 4/11/12 5.4 1.9 21.8 64.8% NO YES 45% YES YES 5/9/12 5 1.9 24 62.0% NO YES 45% YES YES 6/13/12 4.8 2 27.5 58.3% NO NO 45% YES YES 7/11/12 4.8 2.1 28.5 56.3% NO NO 45% YES YES 8/15/12 4.7 2.2 27.5 53.2% NO NO 45% YES YES 9/12/12 4.4 2.2 22 50.0% NO NO 45% YES YES 10/10/12 4.6 2.2 30.5 52.2% NO NO 45% YES YES 11/14/12 5.2 2.6 31.5 50.0% NO NO 45% YES YES 12/12/12 6.1 2.1 22.5 65.6% NO NO 45% YES YES 1/16/13 5.8 2.3 22.5 60.3% NO NO 45% YES YES 2/13/13 5 1.9 21 62.0% NO YES 45% YES YES 3/20/13 4.5 2.3 24.5 48.9% NO NO 45% YES YES 4/10/13 4.9 2 22.5 59.2% NO NO 45% YES YES 5/8/13 5.3 2 26.5 62.3% NO NO 45% YES YES 6/12/13 5 2.3 27 54.0% NO NO 45% YES YES 7/10/13 5.2 2.7 27.5 48.1% NO NO 45% YES YES 8/7/13 5.3 2.3 30.5 56.6% NO NO 45% YES YES 9/11/13 5.4 2.5 29.5 53.7% NO NO 45% YES YES 10/21/13 5.1 2.5 30.5 51.0% NO NO 45% YES YES 11/13/13 5 2.5 36.6 50.0% NO NO 45% YES YES 12/11/13 5.2 2.5 33.5 51.9% NO NO 45% YES YES
Stage 1 Compliance
Over the reporting period, the City sampled six sites in the distribution system for TTHM and HAA5 on a quarterly basis for Stage 1 D/DBP monitoring from January 2009 to August 2012. The City converted to the two Stage 2 D/DBP monitoring sites in November 2012. Between January 2009 and August 2012, the TTHM RAA ranged from 57.1 to 74 μg/L, with an average of 67.3 μg/L. The HAA5 RAA ranged from 37.9 to
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 5-6 2014 UPDATE – FINAL REPORT SECTION 5 – INTAKE EVALUATION
56.5 μg/L, with an average of 49.8 μg/L. Over this reporting period, RAAs are well below the MCLs per the Stage 1 D/DBP Rule.
Stage 2 Compliance
As stated above, the City converted to the two Stage 2 D/DBP monitoring sites in November 2012. Both sites are existing Stage 1 sites. TTHM LRAAs ranged from 55 to 59 μg/L for Site 2 (3029 St. Helena Hwy) and ranged from 58 to 62 μg/L for Site 6 (Knoll Place). HAA5 LRAAs ranged from 48 to 55 μg/L for site 2, and from 53 to 55 μg/L for site 6. Over the reporting period, LRAAs are well below the TTHM and HAA5 MCLs per the Stage 2 D/DBP Rule.
Sites 2 and Sites 6 are both Stage 1 and Stage 2 monitoring sites, so there is continuous data over the reporting period. Individual TTHM and HAA5 data are shown in Figures 5-3 and 5-4.
Figure 5-3. City of St. Helena Distribution System TTHM for Sites 2 and 6, January 2009 – December 2013 120
100
80
60
40 TotalTrihalomethanes, ug/L 20
0 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. '09 '09 '09 '09 '10 '10 '10 '10 '11 '11 '11 '11 '12 '12 '12 '12 '13 '13 '13 '13
Site 2 - 3029 St. Helena Hwy Site 6 - Knoll Place
Figure 5-4 shows a large spike in the HAA5 for both sites 2 and 6 in February 2013. As mentioned earlier during the turbidity discussion, this was when low alkalinity in the source water made it difficult to optimize the alum dose.
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 5-7 2014 UPDATE – FINAL REPORT SECTION 5 – INTAKE EVALUATION
Figure 5-4. City of St. Helena Distribution System HAA5 for Sites 2 and 6, January 2009 – December 2013
100
90
80
70
60
50
40
30 Total HaloAcetic TotalHaloAcetic Acids, ug/L
20
10
0 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. Qtr. '09 '09 '09 '09 '10 '10 '10 '10 '11 '11 '11 '11 '12 '12 '12 '12 '13 '13 '13 '13
Site 2 - 3029 St. Helena Hwy Site 6 - Knoll Place
Volatile and Synthetic Organic Compounds
There were no detectable levels of VOCs or SOCs in the raw water for the Louis Stralla WTP during the reporting period.
Detectable Title 22 Constituents
Please refer to Section 3 for manganese and iron sampling results.
Giardia/Virus/Cryptosporidium Reduction Requirements
Based on the E. coli data evaluated in Section 3, 3/4/2-log reduction of Giardia/virus/Cryptosporidium continue to be appropriate reduction requirements for the Louis Stralla WTP.
The Louis Stralla WTP is classified as a conventional filtration plant, and currently receives reduction credit for 2.5-log Giardia, 2.0-log viruses, and 2-log Cryptosporidium for physical removal. Disinfection with chlorine provides 0.5-log credit for Giardia and
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 5-8 2014 UPDATE – FINAL REPORT SECTION 5 – INTAKE EVALUATION
2.0-log credit for viruses. This meets all of the current microbial removal/inactivation requirements of the SWTR and the IESWTR. In 2013, the City received an email from CDPH indicating that the Louis Stralla WTP was classified as Bin 1 for the LT2ESTWR.
Regulatory Compliance Evaluation
The City has been monitoring the raw and treated water for the Louis Stralla WTP for all required Title 22 compliance constituents. Table 5-3 lists the key existing drinking water regulations and a compliance evaluation for these standards at the Louis Stralla WTP. The Louis Stralla WTP is currently in compliance with existing regulations.
Table 5-3. Regulatory Compliance Evaluation City of St. Helena – Louis Stralla WTP Targeted Key Issues and Compliance Status Compounds Phase I, II, and V IOCs, VOCs, SOCs Monitored as required. No MCLs exceeded in the raw water. SWTR Microbial and Turbidity Data continue to support 3/4—log reduction requirement for Giardia/viruses. All operations, monitoring and reporting requirements are met, and all treated water turbidity standards are met. IESWTR and Filter Backwash Microbial and Turbidity All new turbidity standards met. 2-log Rule reduction credit for Cryptosporidium applicable. Stage 1 D/DBP Rule Disinfectants and Step 1 TOC removal ratio is required to Disinfection By- be calculated. 58 out of 60 months Products during study period resulted in ratio greater than 1.0, indicating compliance. TTHM/HAA5 RAAs comply with drinking water standards (<80/60 μg/L, respectively). LT2ESWTR Microbial Classified as Bin 1. Stage 2 D/DBP Rule Disinfectants and Current TTHM/HAA5 LRAAs for Stage 2 Disinfection By- data are below the MCLs (<80/60 μg/L, Products respectively).
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY Page 5-9 2014 UPDATE – FINAL REPORT SECTION 6 – RECOMMENDATIONS
The following recommendations have been developed for this Third Update. Development of recommendations for watershed management actions that are economically feasible and within the authority of the City of St. Helena (City) is critical. Recommendations will be implemented by the City as resources are available.
Continue to optimize treatment during times of varying source water quality (low raw water alkalinity) – i.e. adjust coagulant dose, optimize polymers, implement alternative coagulants such as PAC, reduce flow if possible to increase hydraulic detention times and reduce filtration loading rates, ensure adequate disinfection contact time (CT).
Continue to use jar testing to optimize solids removal and document removal rates under low raw water alkalinity scenarios. Consider application of a streaming current detector to assist with dosing strategy.
Keep track of vineyard developments in the watershed by ensuring that all erosion control plans forwarded by Napa County are reviewed by the City.
Confirm with California Department of Health Services that City is on Schedule 4 for second round of LT2ESWTR monitoring.
Review Operational Evaluation Level requirements in USEPA OEL Guidance Manual and develop plan for implementation in advance.
Continue to evaluate options to remove bullets from the City’s shooting range which could leach contaminants such as arsenic and lead.
BELL CANYON RESERVOIR WATERSHED SANITARY SURVEY 2014 UPDATE - FINAL REPORT Page 6-1
APPENDIX A BIBLIOGRAPHY AND LIST OF CONTACTS
BIBLIOGRAPHY
1996 Bell Canyon Watershed Sanitary Survey, prepared by CH2MHill
2003 Bell Canyon Watershed Sanitary Survey, prepared by Archibald Consulting
“Napa River Watershed Profile: Past and Present Characteristics with Implications for Future Management of the Changing Napa River Valley”, prepared by San Francisco Estuary Institute, March 2012.
Top 5 Pesticides Used in Napa County in 2012 http://www.cdpr.ca.gov/docs/pur/pur11rep/11_pur.htm 2012 Napa County Agricultural Crop Report, produced by the Napa County Office of the Agricultural Commissioner. Storm Water Multiple Application and Report Tracking System (SMARTS) database for Industries with General Industrial Storm Water Permits https://smarts.waterboards.ca.gov/smarts/faces/SwSmartsLogin.jsp
Napa County Stormwater Management Plan, for fiscal years 2003/2004 through 2007/2008, prepared by Napa County Flood Control and Water Conservation District for the City of Napa, Town of Yountville, City of St. Helena, City of Calistoga, and Napa County.
State Water Resources Control Board, 2012-2013 Annual Report for Storm Water Discharges Associated with Industrial Activities for Arkenstone Vineyards LLC.
State Water Resources Control Board, 2011-2012 Annual Report for Storm Water Discharges Associated with Industrial Activities for Arkenstone Vineyards LLC.
State Water Resources Control Board, 2010-2011 Annual Report for Storm Water Discharges Associated with Industrial Activities for Arkenstone Vineyards LLC.
Stormwater Inspection Report, Napa County Department of Planning, Building, and Environmental Services, Arkenstone Winery, 2012.
Stormwater Inspection Report, Napa County Department of Planning, Building, and Environmental Services, Neal Family Vineyards, 2013.
Stormwater Inspection Report, Napa County Department of Planning, Building, and Environmental Services, Ladera Winery, 2011.
Water Quality Control Policy for Siting, Design, Operation, and Maintenance of On-site Wastewater Treatment Systems, June 19, 2012. Prepared by State Water Resources Control Board.
CALFIRE Archived fires http://cdfdata.fire.ca.gov/incidents/incidents_archived
Ranalli, A.J., 2004. A Summary of the Scientific Literature on the Effects of Fire on the Concentration of Nutrients in Surface Waters: U.S. Geological Survey Open-File Report 2004-1296, 23 pages.
CONTACT LIST
Name Agency Phone number/email Bill Johnson SF Regional Water [email protected] Quality Control Board – (510)622-2354 NPDES and WDRs Michelle Rembaum SF Regional Water [email protected] Quality Control Board – General Industrial Permit John Kara Napa County – Land John.Kara@countyof napa.org Use Team – Septic (707)259-8208 System Kim Withrow Napa County – Sewage [email protected] System Monitoring (707)251-1075 Permit Brian Bordona Napa County – Erosion [email protected] Control Plan (707)259-5935 Doug Calhoun Napa County – Storm [email protected] Water 707.253.4839 Jeff Tangen Napa County – GIS [email protected] mapping of wineries (707)259-5934
APPENDIX B SUMMARIES OF LOUIS STRALLA WTP INTAKE DATA
Recycled Raw Water Turbidity Settled Filter #1 Filter #2 Jan-09 1.3 1.5 0.7 0.052 0.056 Feb-09 1.2 2.4 1.2 0.053 0.058 Mar-09 3 5 1.8 0.039 0.048 Apr-09 2 3.7 1.5 0.05 0.057 May-09 2.5 2.6 1.7 0.044 0.043 Jun-09 1.1 1.7 1.2 0.032 0.032 Jul-09 1.5 1.6 0.7 0.038 0.044 Aug-09 2 2 0.7 0.038 0.046 Sep-09 1.8 1.9 0.7 0.035 0.041 Oct-09 1.9 2.3 0.8 0.033 0.039 Nov-09 1.5 2.4 0.6 0.035 0.038 Dec-09 1.2 3 0.7 0.033 0.037 Jan-10 1.6 4.6 1.2 0.036 0.034 Feb-10 2.3 5.4 1.6 0.033 0.038 Mar-10 2.5 4.4 2.3 0.036 0.033 Apr-10 1.2 3.9 1.9 0.042 0.038 May-10 1 2.8 1.4 0.033 0.037 Jun-10 1 1.9 1 0.034 0.04 Jul-10 0.9 1.9 0.6 0.043 0.036 Aug-10 1.4 2.4 0.6 0.031 0.032 Sep-10 1.1 2.9 0.7 0.036 0.038 Oct-10 1.1 2.6 0.8 0.048 0.036 Nov-10 1.1 2.1 0.5 0.041 Dec-10 1.3 2.6 0.9 0.033 0.038 Jan-11 1.8 3.4 2 0.041 0.042 Feb-11 2.3 3.7 2.2 0.037 0.033 Mar-11 2.5 6.5 3.1 0.036 0.033 Apr-11 1.7 6.2 2.3 0.045 0.035 May-11 1.5 4.6 1.3 0.039 0.043 Jun-11 1.4 3.6 1.1 0.037 0.045 Jul-11 0.9 2.3 1 0.056 0.038 Aug-11 1.2 2.8 1 0.034 0.041 Sep-11 1.3 2.6 1 0.034 0.044 Oct-11 1.6 2.7 1.2 0.035 0.043 Nov-11 1 3.8 0.9 0.034 0.036 Dec-11 1.2 8.5 1.3 0.035 0.042 Jan-12 1.6 12 1.6 0.056 0.048 Feb-12 1.5 9.9 1.7 0.046 0.057 Mar-12 2.8 12.2 1.4 0.042 0.05 Apr-12 2.2 10.1 1.8 0.044 0.055 May-12 2 6.8 1.5 0.033 0.04 Jun-12 1.2 4 1.1 0.033 0.042 Jul-12 0.9 2.9 0.6 0.033 0.035 Aug-12 0.9 3 0.5 0.039 0.035 Sep-12 0.9 3.1 0.4 0.042 0.043 Oct-12 0.7 2.4 0.4 0.037 0.043 Nov-12 0.7 2.2 0.5 0.033 0.047 Dec-12 1.9 5.9 2.3 0.034 0.046 Jan-13 1.3 4.7 3.7 0.04 0.06 Feb-13 0.9 3.8 3.4 0.055 0.059 Mar-13 1 3.1 1.5 0.032 0.045 Apr-13 1 2.6 0.7 0.044 0.059 May-13 1.2 2.4 0.5 0.047 0.054 Jun-13 1.5 2.6 0.5 0.052 0.054 Jul-13 2 4.1 0.4 0.045 0.055 Aug-13 2.1 3.1 0.4 0.039 0.047 Sep-13 1.4 4.1 0.5 0.04 0.053 Oct-13 1.2 3.1 0.5 0.033 0.051 Nov-13 1.4 4.1 0.6 0.035 0.044 Dec-13 1.2 5.1 0.5 0.04 0.053 min 0.7 1.5 0.4 0.031 0.032 max 3 12.2 3.7 0.056 0.06 ave 1.49 3.93 1.19 0.04 0.04 median 1.35 3.1 1 0.037 0.043 95th 2.5 9.91 2.34 0.0532 0.05805 Ave. Percent removal 0.697793 Raw Total Raw Coliform e. Coli MPN/100 MPN/100 Date mL mL 1/14/2009 39.9 <1.0 1/28/2009 43 1.0 2/11/2009 218.7 <1.0 2/26/2013 2419.2 13.2 3/25/2009 260.2 <1.0 3/11/2009 > 2419 <1.0 4/8/2009 125 <1.0 4/22/2009 1413.6 1.0 5/7/2009 2419.2 1.0 5/2/2009 222.4 <1.1 6/3/2009 325.5 <1.0 7/1/09 178.5 < 1.0 7/8/09 248.9 5.2 7/15/09 410.6 < 1.0 11/13/2009 >2400 ND 12/10/2009 69 ND 1/13/2010 920.8 5.1 2/10/2010 410.6 4.1 3/10/2010 1986.3 3.1 4/14/2010 686.7 12.2 5/12/2010 >2419 1.0 6/9/2010 71.2 1.0 7/15/2010 520 3.1 8/11/2010 579.4 <1.0 9/8/2010 1046.2 1.0 10/13/2010 344.8 <1 11/10/2010 >2419 8.6 12/8/2010 2419.2 4.1 1/12/2011 365.4 1.0 2/9/2011 195.6 <1 3/9/2011 149.7 <1 4/13/2011 172.2 4.1 5/11/2011 >2419 < 1.0 6/22/2011 21.3 < 1.0 7/13/2011 > 2419 3.1 8/10/201 1299.7 2.0 10/12/2011 > 2419 < 1.0 11/9/2011 1553.1 1.0 12/14/2011 108.1 3.1 1/10/2012 261.3 14.6 2/8/2012 325.5 2.0 3/14/2012 <2419 21.1 4/11/2012 46.4 <1.0 5/9/2012 >2419 <1.0 6/13/2012 98.7 17.3 7/11/2012 41.3 < 1.0 8/8/2012 410.6 < 1.0 9/12/2012 193.5 < 1.0 10/10/2012 127.4 < 1.0 11/14/2012 325.5 <1.0 12/12/2012 579.4 3.1 1/10/2013 ? 0 ND 2/13/2013 21.8 <1.0 3/13/2013 130.9 <1 4/10/2013 488.4 1.0 5/8/2013 NA NA 6/12/2013 365.4 1.0 7/11/2013 1732.9 <1.0 8/7/2013 816.4 40.4 9/11/2013 866.4 1.0 10/9/2013 > 2419 < 1.0 11/13/2013 727 2.0 12/12/2013 49.6 4.1 Data for Sanitary Survey Update Yr.2014 BCR & LSWTP
Treated Treated Raw TOC Water Raw Alk Percent Raw TOC TOC < 2 Required Actual > Met Enhanced Date TOC mg/L Removal <2 mg/L mg/L Removal Required Coagulation? 1/14/09 4.1 2.6 25 36.6% NO NO 45% NO NO 2/11/09 3.8 2.2 29 42.1% NO NO 35% YES YES 3/11/09 5.7 2.4 27.5 57.9% NO NO 45% YES YES 4/8/09 5.6 2.6 25 53.6% NO NO 45% YES YES 5/20/09 4.3 2.1 28.5 51.2% NO NO 45% YES YES 6/10/09 4.2 2.0 23.5 52.4% NO NO 45% YES YES 7/8/09 5 2.4 37.8 52.0% NO NO 45% YES YES 8/12/09 4.7 2.3 27.5 51.1% NO NO 45% YES YES 9/9/09 5.3 2.5 30.5 52.8% NO NO 45% YES YES 10/14/09 5.9 2.7 29 54.2% NO NO 45% YES YES 11/17/09 5.2 2.8 30 46.2% NO NO 45% YES YES 12/10/09 5 2.8 33.5 44.0% NO NO 45% NO NO 1/13/10 4.8 2.2 33.5 54.2% NO NO 45% YES YES 2/10/10 5.6 2.4 21 57.1% NO NO 45% YES YES 3/10/10 5 1.9 22 62.0% NO YES 45% YES YES 4/14/10 4.9 0.5 21 89.8% NO YES 45% YES YES 5/12/10 4.4 1.8 29 59.1% NO YES 45% YES YES 6/9/10 4.1 1.9 26.5 53.7% NO YES 45% YES YES 7/15/10 5 2.6 28 48.0% NO NO 45% YES YES 8/11/10 4.1 2.1 25 48.8% NO NO 45% YES YES 9/8/10 4.5 1.9 32 57.8% NO YES 45% YES YES 10/13/10 4.5 1.9 32.5 57.8% NO YES 45% YES YES 11/10/10 4.3 1.9 29 55.8% NO YES 45% YES YES 12/8/10 4.4 1.9 29 56.8% NO YES 45% YES YES 1/12/11 4.7 1.8 24.5 61.7% NO YES 45% YES YES 2/9/11 4.7 1.8 27 61.7% NO YES 45% YES YES 3/16/11 4.7 1.7 24.5 63.8% NO YES 45% YES YES 4/13/11 3.8 1.6 23 57.9% NO YES 35% YES YES 5/11/11 4 1.9 25 52.5% NO YES 45% YES YES 6/9/11 4.6 2.2 30 52.2% NO NO 45% YES YES 7/13/11 3.6 1.7 28 52.8% NO YES 35% YES YES 8/10/11 4.1 1.8 30.5 56.1% NO YES 45% YES YES 9/14/11 3.8 1.8 33 52.6% NO YES 35% YES YES 10/12/11 4 1.8 29 55.0% NO YES 45% YES YES 11/9/11 3.5 1.7 32 51.4% NO YES 35% YES YES 12/14/11 4 2 22 50.0% NO NO 45% YES YES 1/11/12 3.4 1.9 28.5 44.1% NO YES 35% YES YES 2/8/12 4.9 2.1 22.5 57.1% NO NO 45% YES YES 3/14/12 5.5 2 26 63.6% NO NO 45% YES YES 4/11/12 5.4 1.9 21.8 64.8% NO YES 45% YES YES 5/9/12 5 1.9 24 62.0% NO YES 45% YES YES 6/13/12 4.8 2 27.5 58.3% NO NO 45% YES YES 7/11/12 4.8 2.1 28.5 56.3% NO NO 45% YES YES 8/15/12 4.7 2.2 27.5 53.2% NO NO 45% YES YES 9/12/12 4.4 2.2 22 50.0% NO NO 45% YES YES 10/10/12 4.6 2.2 30.5 52.2% NO NO 45% YES YES 11/14/12 5.2 2.6 31.5 50.0% NO NO 45% YES YES 12/12/12 6.1 2.1 22.5 65.6% NO NO 45% YES YES 1/16/13 5.8 2.3 22.5 60.3% NO NO 45% YES YES 2/13/13 5 1.9 21 62.0% NO YES 45% YES YES 3/20/13 4.5 2.3 24.5 48.9% NO NO 45% YES YES 4/10/13 4.9 2 22.5 59.2% NO NO 45% YES YES 5/8/13 5.3 2 26.5 62.3% NO NO 45% YES YES 6/12/13 5 2.3 27 54.0% NO NO 45% YES YES 7/10/13 5.2 2.7 27.5 48.1% NO NO 45% YES YES 8/7/13 5.3 2.3 30.5 56.6% NO NO 45% YES YES 9/11/13 5.4 2.5 29.5 53.7% NO NO 45% YES YES 10/21/13 5.1 2.5 30.5 51.0% NO NO 45% YES YES 11/13/13 5 2.5 36.6 50.0% NO NO 45% YES YES 12/11/13 5.2 2.5 33.5 51.9% NO NO 45% YES YES
min 3.4 0.5 21.0 36.6% max 6.1 2.8 37.8 89.8% average 4.7 2.1 27.5 55.0% median 4.8 2.1 27.5 53.9% 95th percentile 5.705 Sites: 1. Niebaum Ln. @Church (Max. Residence time southeast zone 1) 2. 3029 St. Helena Hwy. (Max. Residence time northwest zone1) 3. Pratt Ave. (Mean Residence time zone 1) 4. 1240 Oak St. (Mean Residence time zone1) 5. Holmes Tank 6. Knoll Place Running In Qrt. Sites Quarterly Annual Compliance Month Day Year Test 1 2 3 4 5 6 Average Average Yes/No? 2009 TTHM 0.047 0.018 0.050 0.045 0.040 0.064 1 February 19 Yes 2009 HAA5 0.022 0.064 0.083 0.079 0.062 0.057 2009 TTHM 0.065 0.068 0.060 0.082 0.069 0.0678 2 May 20 Yes 2009 HAA5 0.026 0.088 0.090 0.049 0.063 0.060 2009 TTHM 0.078 0.085 0.070 0.079 0.084 0.071 0.078 0.066 3 August 26 Yes 2009 HAA5 0.034 0.068 0.062 0.059 0.005 0.068 0.049 0.059 2009 TTHM 0.065 0.110 0.078 0.080 0.086 0.098 0.086 0.068 4 November 26 Yes 2009 HAA5 0.015 0.067 0.061 0.060 0.037 0.068 0.051 0.056 2010 TTHM 0.038 0.057 0.059 0.039 0.054 0.075 0.054 0.072 1 February 17 Yes 2010 HAA5 0.005 0.043 0.077 0.048 0.069 0.083 0.054 0.055 2010 TTHM 0.073 0.056 0.063 0.065 0.075 0.080 0.069 0.0716 2 May 19 Yes 2010 HAA5 0.045 0.051 0.060 0.062 0.078 0.062 0.060 0.054 2010 TTHM 0.070 0.063 0.050 0.078 0.091 0.049 0.067 0.069 3 August 25 Yes 2010 HAA5 0.038 0.060 0.051 0.072 0.084 0.056 0.060 0.056 2010 TTHM 0.039 0.098 0.075 0.032 0.051 0.083 0.063 0.063 4 November 17 Yes 2010 HAA5 0.014 0.068 0.058 0.022 0.002 0.064 0.038 0.053 2011 TTHM 0.077 0.100 0.056 0.082 0.053 0.063 0.072 0.068 1 February 16 Yes 2011 HAA5 0.076 0.064 0.067 0.079 0.032 0.069 0.065 0.056 2011 TTHM 0.092 0.083 0.073 0.062 0.053 0.078 0.074 0.069 2 May 18 Yes 2011 HAA5 0.041 0.060 0.058 0.039 0.013 0.061 0.045 0.052 2011 TTHM 0.100 0.091 0.079 0.088 0.085 0.084 0.088 0.074 3 August 24 Yes 2011 HAA5 0.045 0.061 0.059 0.040 0.026 0.057 0.048 0.049 2011 TTHM 0.036 0.072 0.056 0.062 0.057 0.063 0.058 0.073 4 November 16 Yes 2011 HAA5 0.008 0.053 0.048 0.048 0.020 0.051 0.038 0.049 2012 TTHM 0.035 0.043 0.037 .0.027 0.045 0.014 0.035 0.063 1 February 16 Yes 2012 HAA5 0.024 0.033 0.029 0.022 0.023 0.029 0.027 0.040 2012 TTHM 0.057 0.070 0.058 0.072 0.073 0.063 0.066 0.061 2 May 18 Yes 2012 HAA5 0.036 0.057 0.052 0.049 0.037 0.058 0.048 0.040 2012 TTHM 0.054 0.087 0.071 0.074 0.065 0.079 0.072 0.057 3 August 24 Yes 2012 HAA5 0.023 0.052 0.042 0.040 0.027 0.048 0.039 0.038 2012 TTHM 0.033 0.078 0.071 0.064 0.039 0.073 0.060 0.058 4 November 16 Yes 2012 HAA5 0.006 0.018 0.056 0.045 0.000 0.057 0.030 0.036 2013 TTHM 0.067 0.061 0.054 0.048 0.038 0.062 0.055 0.067 1 February 16 Yes 2013 HAA5 0.000 0.088 0.086 0.076 0.009 0.089 0.058 0.060 2013 TTHM 0.044 0.055 2 May 15 2013 HAA5 0.039 0.026 2013 TTHM 0.053 0.056 3 August 21 2013 HAA5 0.046 0.048 = Start Stage 2 Compliance 1 2 3 4 5 6
Water System Name: City of St. Helena System No. 2810004
APPENDIX C BELL CANYON RESERVOIR WATERSHED MAP .! Legend %2
Bell Canyon Watershed
Vineyards within Watershed = 262.18 Ac. Wineries Wineries in Vicinity
.! Producing
%2 Approved
SEARS WINERY &3 .! Pending
SUMMIT LAKE VINEYARDS .! ROBERT CRAIG WINERY ! OUTPOST WINES ROBERT FOLEY VINEYARDS . .! %2
DUNN VINEYARDS .!
1.39Ac.
2.47Ac. CIMAROSSA WINERY 3.25Ac. O'SHAUGHNESSY%2 WINERY .! 3.91Ac. 5.06Ac. 6.95Ac. 6.92Ac. 5.2Ac. SHUTTERS WINERY 2.1Ac. %2 WHITE COTTAGE RANCH WINERY 1.54Ac. .!
4.12Ac.
17.71Ac. 0.6Ac.
1.02Ac. 1.31Ac. 13.3Ac.6.89Ac. 0.22Ac. 1.81Ac. 3.38Ac. 0.36Ac. 0.25Ac. 0.66Ac. 3.19Ac. 2.38Ac.
13.71Ac. 6.86Ac. 0.84Ac. 1.98Ac. 0.15Ac. 0.23Ac. 0.96Ac. 0.58Ac. .! 1.75Ac. 6.49Ac.
1.03Ac. 10.23Ac. 1.37Ac. 1.49Ac. DIOGENES RIDGE WINERY&3 1.03Ac. 2.46Ac. 0.97Ac.0.5Ac. 0.36Ac. 0.08Ac. LAIL VINEYARDS 3.41Ac. %2 LADERA WINERY 0.41Ac. 0.75Ac. .! BRAVANTE WINERY 0.54Ac. 6.22Ac. 3.39Ac. .! 1.79Ac. 29.99Ac.
0.78Ac. 6.24Ac. 0.17Ac. .! 5.41Ac. ARKENSTONE VINEYARDS
STONEY SPRINGS 5.12Ac. .! CADE WINERY VIADER VINEYARDS0.83Ac. .! 21.23Ac. .! VINEYARD 22 MASKED MAN WINERY %2 %2 DANCING HARES VINEYARD 26.77Ac. BURGESS CELLARS .! .!
MERUS WINES BENESSERE .! .! BREMER FAMILY WINERY .! BROMAN CELLARS TUDAL WINERY EHREN JORDAN WINE CELLARS .! .! %2 .! County of Napa
Bell Canyon Watershed P. B. E. S.
Disclaimer: This map was prepared for informational Horizontal Datum: NAD 83, purposes only. No liability is assumed for the accuracy CA State Plane Coordinates, of the data delineated hereon. Zone II, feet Revised Date: 11/2013