www.lhs.berkeley.edu/exhibits/water/pdfs/WW-Ed-Guide.pdf
Filetype:
pdf
Filesize: 2131317
California Department of Water Resources
Division of Operations and Maintenance
Water Quality Section
Water Quality Assessment of
the State Water Project, 1998-99
July 2000
Gray Davis
Mary D. Nichols Thomas M. Hannigan
Governor
Secretary for Resources
Director
State of California The Resources Agency Department of Water Resources
Contents
Organization .......................................................................................................................................iii
Acronyms and Abbreviations Used ......................................................................................................xi
I. Executive Summary..................................................................................................................... 1
Annual and Seasonal Trends ........................................................................................................... 1
North Bay Aqueduct................................................................................................................. 1
South Bay Aqueduct ................................................................................................................ 2
San Luis Reservoir ................................................................................................................... 2
California Aqueduct ................................................................................................................. 2
Project Lakes in Southern California .......................................................................................... 3
Non-Project Inflows...................................................................................................................... 4
Floodwater Inflow to the San Luis Canal.................................................................................. 4
Inflow from the Kern River Intertie and Cross Valley Canal...................................................... 4
Natural Inflow to Project Lakes in Southern California ............................................................. 5
II. Introduction................................................................................................................................ 7
Objectives ................................................................................................................................... 7
Monitoring Strategy...................................................................................................................... 7
Water Quality Standards and Objectives......................................................................................... 7
III. Annual and Seasonal Trends ..................................................................................................... 9
Conventional Parameters and Major Minerals ............................................................................... 9
Feather River Watershed....................................................................................................... 9
North and South Bay Aqueducts and San Luis Reservoir ......................................................... 9
California Aqueduct and Coastal Branch ................................................................................ 17
Project Lakes in Southern California ......................................................................................... 24
Minor Elements............................................................................................................................. 31
Feather River Watershed......................................................................................................... 31
North and South Bay Aqueducts and San Luis Reservoir ........................................................... 31
California Aqueduct and Coastal Branch .................................................................................. 31
Project Lakes in Southern California ......................................................................................... 37
Trihalomethane Precursors and Formation Potential....................................................................... 39
North and South Bay Aqueducts and San Luis Reservoir ........................................................... 39
California Aqueduct and Coastal Branch .................................................................................. 41
ii
Project Lakes in Southern California ......................................................................................... 45
Organic Chemicals ....................................................................................................................... 46
IV. Non-Project Inflows ................................................................................................................... 49
Floodwater Inflows to the San Luis Canal....................................................................................... 49
Inflow Volumes ...................................................................................................................... 49
Floodwater Quality.................................................................................................................. 50
Aqueduct Water Quality.......................................................................................................... 55
Inflow from the Kern River Intertie and Cross Valley Canal........................................................... 60
Natural Inflow to Project Lakes in Southern California .................................................................. 63
Pyramid Lake ......................................................................................................................... 63
Castaic Lake .......................................................................................................................... 63
Silverwood Lake ..................................................................................................................... 66
List of Tables
3-1 Conventional Parameters and Major Minerals in the Feather River Watershed, 1998-99.................... 10
3-2 Minor Elements in the Feather River Watershed, 1998-99 ............................................................... 32
3-3 Metallic Elements in the North and South Bay Aqueducts and San Luis Reservoir, 1998-99 .............. 33
3-4 Nonmetallic Elements in the North and South Bay Aqueducts and San Luis
Reservoir, 1998-99 .................................................................................................................. 34
3-5 Metallic Elements in the California Aqueduct and Coastal Branch, 1998-99...................................... 35
3-6 Nonmetallic Elements in the California Aqueduct and Coastal Branch, 1998-99 ................................ 37
3-7 Minor Elements in Project Lakes in Southern California, 1998-99..................................................... 38
3-8 Organic Chemicals in the State Water Project, 1998-99 .................................................................. 47
4-1 General Water Quality Parameters in Floodwater Inflow ................................................................ 51
4-2 Minor Element Concentrations in Floodwater Inflow, 1998 .............................................................. 54
4-3 Pesticides and Herbicides in Floodwater Inflow, 1998 ..................................................................... 55
4-4 Water Quality in the Kern River Intertie and Cross Valley Canal, 1998............................................ 61
4-5 Minor Elements in the Kern River Intertie and Cross Valley Canal, 1998 ......................................... 61
List of Figures
1-1 Annual Water Quality Summary in the North and South Bay Aqueducts and San Luis Reservoir ....... 1
1-2 Annual Water Quality Summary in the California Aqueduct ............................................................ 3
iii
1-3 Annual Water Quality Summary at Project Lakes in Southern California .......................................... 4
3-1
Conventional Parameters in the North and South Bay Aqueducts and
San Luis Reservoir, 1998-99 ........................................................................................................ 11
3-2 Major Minerals in the North and South Bay Aqueducts and San Luis Reservoir, 1998-99 .................. 13
3-3 Monthly TDS and Turbidity in the North and South Bay Aqueducts and San Luis Reservoir .............. 15
3-4
Monthly Sulfate, Chloride, and Hardness in the North and South Bay Aqueducts and
San Luis Reservoir ...................................................................................................................... 16
3-5 Conventional Parameters in the California Aqueduct and Coastal Branch, 1998-99 ........................... 18
3-6 Major Minerals in the California Aqueduct and Coastal Branch, 1998-99.......................................... 20
3-7 Monthly TDS and Turbidity in the California Aqueduct................................................................... 22
3-8 Monthly Sulfate, Chloride, and Hardness in the California Aqueduct ................................................ 23
3-9 Conventional Parameters at Project Lakes in Southern California, 1998-99....................................... 25
3-10 Major Minerals at Project Lakes in Southern California, 1998-99 .................................................... 27
3-11 Quarterly Sulfate, Chloride, and Hardness at Project Lakes in Southern California ........................... 29
3-12 Quarterly TDS and Turbidity at Project Lakes in Southern California .............................................. 30
3-13 Bromide, TOC, and TTHMFP in the North and South Bay Aqueducts and San Luis Reservoir ......... 39
3-14 Monthly TOC and TTHMFP in the North and South Bay Aqueducts and San Luis Reservoir ........... 40
3-15 Bromide, TOC, and TTHMFP in the California Aqueduct and Coastal Branch, 1998-99................... 42
3-16 Monthly TOC and Bromide in the California Aqueduct................................................................... 43
3-17 Monthly TTHMFP in the California Aqueduct............................................................................... 44
3-18 Quarterly TOC, Bromide, and TTHMFP in Project Lakes in Southern California ............................. 46
4-1 Annual Floodwater Inflow Volumes to San Luis Canal, 1973-99 ...................................................... 49
4-2 Monthly Floodwater Inflow per Drain Inlet..................................................................................... 50
4-3 Historical Water Quality of Drain Inlets ......................................................................................... 51
4-4 Mineralogy of Little Panoche Creek and Seawater with TDS.......................................................... 53
4-5 Mineralogy of all Drain Inlets Combined with TDS......................................................................... 54
4-6
Percentage of Water Diverted out of the SLC by Federal Contractors, February-June 1998.............. 55
4-7 Daily Conductivity at Checks 13, 18, and 21, February-June 1998 .................................................... 56
4-8 Daily Turbidity at Checks 13, 18, and 21, February-June 1998 ......................................................... 57
4-9 Daily Flow Past Check 21, February-June 1998.............................................................................. 57
4-10 Mineralogical Makeup of Water at Checks 13 and 21, February 18, 1998 ........................................ 58
4-11 Water Quality in the San Luis Canal at Checks 13 and 21, January-July 1998 .................................. 59
4-12 Kern River Intertie and Cross Valley Canal Inflows to the California Aqueduct, April-July 1998....... 60
iv
4-13 Pumping at Buena Vista Pumping Plant and Check 28 Flow in the Aqueduct, April-July 1998........... 61
4-14 Daily Conductivity in the Aqueduct, Kern River Intertie, and Cross Valley Canal,
April-July 1998 ........................................................................................................................ 62
4-15 Daily Turbidity in the Aqueduct, Kern River Intertie, and Cross Valley Canal,
April-July 1998......................................................................................................................... 63
4-16 Water Quality Sampling Stations on Pyramid Lake......................................................................... 64
4-17 Monthly Inflows to Pyramid Lake, 1998-99 ................................................................................... 64
4-18 Water Quality Sampling Stations on Castaic Lake .......................................................................... 65
4-19 Monthly Inflows to Castaic Lake, 1998-99..................................................................................... 65
4-20 TDS in Castaic and Pyramid Lakes, 1998-99................................................................................. 66
4-21 Water Quality Sampling Stations on Silverwood Lake..................................................................... 67
4-22 Monthly Project and Natural Inflows to Silverwood Lake, 1998-99.................................................. 67
4-23 TDS in Silverwood Lake and Its Inflows/Outflows, 1998-99 ........................................................... 68
References ....................................................................................................................................... 69
Appendices
Appendix A (Methods).................................................................................................................... 70
Appendix B (Water Quality Standards and Objectives)....................................................................... 87
Appendix C (Data Tables)................................................................................................................ 93
Appendix D (Explanation of Trilinear Plots) .......................................................................................115
v
State of California
Gray Davis, Governor
The Resources Agency
Mary D. Nichols
Secretary for Resources
Department of Water Resources
Thomas M. Hannigan
Director
Jonas Minton
Steve Macaulay
Raymond D. Hart
Deputy Director
Chief Deputy Director
Deputy Director
L. Lucinda Chipponeri Susan N. Weber
Assistant Director for Legislation Chief Counsel
Division of Operations and Maintenance
Steven L. Kashiwada, Chief
Gary Gravier, Chief, Water and Plant Engineering Office
This report was prepared under the supervision of
Daniel F. Peterson, Chief, Environmental Assessment Branch
By
Barry L. Montoya, Environmental Specialist IV (Spec.)
vi
Database Management
Larry D. Joyce, Chief, Water Quality Section
Chris Erickson, Environmental Specialist II
Bryte Laboratory
William C. Nickels, Chief
Sidney Fong, P.H. Chemist III (Supv.)
Mark Bettencourt, Lab. Tech.
Guy Gilbert, P.H. Chemist II
Richard Hernandez, P.H. Chemist II
Jack R. Kersh, Bus. Serv. Asst.
M. Pineda, P.H Chemist I
Josie Quiambo, P.H. Chemist II
Mercedes Tescon, P.H. Chemist I
Pritam Thind, P.H. Chemist II
E. Wong, P.H. Chemist II
Oroville Field Division,
Beckwourth Subcenter
Ralph D. Howell, WSS
Ron Vanscoy, WREA (Spec.)
Robert Carbajal, WREA (Spec.)
Oroville Field Division, Headquarters
Ed Robbins, WSS, Water Operations
John F. Knox, Water Res.Tech. II
Kathie S. Lopez, Water Res.Tech. II
Thomas F. Odekirk, Water Res.Tech. II
Printed by DWR Reprographics
Delta Field Division
George M. Anderson, Chief, Water
Operations
Richard H. Gage, WREA
Mike A.Taliaferro, Water Res.Tech.II
Doug A.Thompson, WREA
San Luis Field Division
Pam Anaya, Chief, Surveillance and
Monitoring Unit
Nikki Griffin, Water Res.Tech. II
Ernie Severino, Water Res.Tech. II
San Joaquin Field Division
Wayne Archer, Chief, Water Operations
Richard Albidrez, Jr. Eng.Tech.
Jennifer Metcalf, Water Res.Tech. II
Southern Field Division
John Kemp, Chief, Water Quality Unit
Gary Faulconer, Environmental Spec.IV
William Jorden, Water Res.Tech. I
Michelle Leonard, T & D
Della Stephenson, Water Res.Tech. II
Water Quality Assessment of the State Water Project, 1998-99
1 Executive Summary
I. Executive Summary
This report describes water quality in the State Water Project during 1998 and 1999. The Executive
Summary covers important drinking water parameters such as salinity and trihalomethane precursors. The
rest of the report assesses all parameters including metals and pesticides.
Annual and Seasonal Trends
North Bay Aqueduct
In the North Bay Aqueduct at Barker Slough Pumping Plant, the median and range of water quality
parameters were similar between 1998 and 1999 (Figure 1-1). TDS ranged from 90 to 300 mg/L and was
highest in late spring and early summer of both years. Similar trends were observed for sulfate, chloride,
hardness, and bromide. Bromide was highest each April but never exceeded 0.1 mg/L.
Figure 1-1
Annual Water Quality Summary in the North and South Bay Aqueducts and
San Luis Reservoir
mg/L
50
100
150
200
250
300
350
400
450
TDS
mg/L
0
20
40
60
80
100
120
140
160
Chloride
mg/L
0
10
20
30
40
50
60
70
Sulfate
mg/L
0
4
8
12
16
20
24
TOC
mg/L
0.0
0.1
0.2
0.3
0.4
0.5
Bromide
mg/L(as CaC03)
20
40
60
80
100
120
140
160
180
NBA, Barker Sl. PP
SBA,Check7
SBA, Terminal Tank
San Luis Reservoir
.
NBA, Barker Sl. PP
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
Hardness
1999
1998
micro g/L
200
400
600
800
1000
1200
1400
1600
1800
NBA, Barker Sl. PP
SBA,Check7
SBA, Terminal Tank
San Luis Reservoir
.
NBA, Barker Sl. PP
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
TTHMFP
1998
1999
Water Quality Assessment of the State Water Project, 1998-99
Executive Summary
2
TOC at Barker Slough Pumping Plant was highest during the winter months with a maximum of 20 mg/L
in January 1998 and 14.4 mg/L in February 1999. The same samples contained peak TTHMFP levels of
1,583 and 1,689
µ
g/L, respectively. Rainfall runoff from the upstream watershed was responsible for
these increases.
South Bay Aqueduct
Median TDS at Check 7 on the South Bay Aqueduct was 139 mg/L in 1998 and 208 mg/L in 1999, with a
combined range of 85 to 386 mg/L (Figure 1-1). A maximum of 386 mg/L was measured in December
1999 along with peak chloride and bromide levels (151 mg/L and 0.52 mg/L, respectively). Nearly
identical levels were detected at Banks Pumping Plant in that same month. The increases in December
were related to salinity intrusion in the south Delta. Salinity trends at Check 7 on the South Bay Aqueduct
were similar to those at Banks Pumping Plant on the California Aqueduct. Monthly salt concentrations at
these two stations covaried with r-squared values ranging from 0.96 for sulfate to 0.99 for chloride.
TOC at Check 7 ranged between 3 and 6 mg/L. Monthly levels were somewhat correlated with those at
Banks Pumping Plant (r-squared = 0.76) but were sometimes off by +-1.5 mg/L. Organic carbon levels
may be affected as water is pumped through Bethany Reservoir prior to reaching Check 7.
San Luis Reservoir
In San Luis Reservoir, turbidity remained below 5 NTU and TDS ranged between 226 and 295 mg/L
during the 2-year period (Figure 1-1). In 1998, chloride declined from 76 mg/L in August to 65 mg/L in
October. The decline was a result of reservoir filling with low-salinity water from the south Delta.
Chloride (and salinity in general) has been steadily declining in the reservoir since 1991, when it peaked
at 149 mg/L (TDS = 420 mg/L). The higher levels were due to past lake filling during the 1989-92
drought. Bromide sampling was initiated in 1999 and all values were around 0.2 mg/L.
California Aqueduct
Salinity was highly variable in the California Aqueduct during 1998-99. TDS at Banks Pumping Plant
ranged from 85 to 400 mg/L during the 2-year period (Figure 1-2). It remained low (85-146 mg/L)
throughout the summer of 1998 due to a wet season and high runoff in the Central Valley. These effects
were observed throughout the Aqueduct. The following year, TDS at Banks Pumping Plant increased to
388 mg/L in December along with chloride (151 mg/L) and bromide (0.52 mg/L). That month, the south
Delta experienced salinity intrusion due, in part, to closure of the Cross Channel Gates. Further down the
Aqueduct, salinity in the San Luis Canal increased because of floodwaters during February 1998. Federal
deliveries removed 48 percent of the total inflow to the canal that month and likely reduced the loads
contributed by floodwaters. In April 1998, east-side inflows from the Kern, Kaweah, and Tulare rivers
lowered Aqueduct TDS—and other salt-related parameters like bromide—by more than 50 percent. These
inflows accounted for most Aqueduct flow south of Check 29 for three consecutive months. There were
no river or floodwater inflows in 1999.
TOC in the California Aqueduct ranged from 2.1 to 9.3 mg/L over the 2-year period. TOC was unusually
elevated at Check 13 in January 1998 (7.2 mg/L). Based on inflows to O’Neill Forebay, the high level
originated from the Delta Mendota Canal and San Luis Reservoir. A maximum value of 9.3 mg/L was
measured at Check 41 in January 1998. The high level may have resulted from a short-duration slug that
made its way down the Aqueduct and passed Check 41 at the time of sampling. An on-line organic carbon
monitor has been installed at Clifton Court Forebay to track such short-duration trends.
Water Quality Assessment of the State Water Project, 1998-99
3 Executive Summary
Figure 1-2
Annual Water Quality Summary in the California Aqueduct
Project Lakes in Southern California
Water quality samples are collected quarterly at Project Lakes in Southern California (Figure 1-3). In
Pyramid Lake, mean TDS, sulfate, and hardness levels were slightly higher in 1998 than in 1999 due, in
part, to above-normal inflow from Piru Creek. The creek has a high TDS (average = 554 mg/L) with high
sulfate and hardness relative to chloride. These mineralogical traits were reflected in Pyramid Lake from
May 1998 to February 1999 and in Castaic Lake for most of the 2-year period. TDS was lowest in
Silverwood Lake due, in part, to low-salinity inflow from the surrounding watershed.
TOC in Castaic Lake ranged between 2.5 and 3.7 mg/L in all but one sample. The February 1999 sample
contained 7.7 mg/L but did not correspond with any major inflow event—Project inflow was zero for the
month and natural inflow was below normal. Routine bromide monitoring was initiated at all lakes in
1999 and values ranged from 0.09 to 0.15 mg/L, except at Lake Perris where bromide averaged 0.21
mg/L.
mg/L
50
100
150
200
250
300
350
400
450
TDS
mg/L
0
20
40
60
80
100
120
140
160
180
Chloride
mg/L
0
10
20
30
40
50
60
70
80
Sulfate
mg/L(as CaC03)
20
40
60
80
100
120
140
Banks Pumping Plant
Check 13
Check 41
Devil CanyonAfterbay
Banks Pumping Plant
Check 13
Check 41
Devil CanyonAfterbay
Hardness
1999
1998
mg/L
0.0
0.1
0.2
0.3
0.4
0.5
Bromide
mg/L
1
2
3
4
5
6
7
8
9
10
TOC
micro g/L
100
200
300
400
500
600
700
800
Banks Pumping Plant
Check 13
Check 41
Devil CanyonAfterbay
Banks Pumping Plant
Check 13
Check 41
Devil CanyonAfterbay
TTHMFP
1998
1999
Water Quality Assessment of the State Water Project, 1998-99
Executive Summary
4
Figure 1-3
Annual Water Quality Summary at Project Lakes in Southern California (n=1-4)
Non-Project Inflows
Floodwater Inflow to the San Luis Canal
Floodwater inflow to the San Luis Canal totaled 20,578 af in 1998—the fifth highest volume behind
1973, 1978, 1983, and 1985. Eighty-six percent of the inflow was in February and 31 percent of that was
from Cantua Creek, followed by Little Panoche Creek (25 percent) and Arroyo Pasajero (12 percent). In
the same month, federal contractors diverted about half of all inflows (Project and floodwater) to the
canal for pre-irrigation purposes. Although these diversions tended to minimize water quality impacts to
the Aqueduct, floodwaters raised conductivity by 50 to 400
µ
S/cm (30-230 mg/L calculated TDS) for
more than a month. There were no floodwaters in 1999.
Inflow from the Kern River Intertie and Cross Valley Canal
In the first half of 1998, 198,446 af from the Kern, Tulare, and Kaweah rivers was admitted to the
California Aqueduct just prior to Check 29. Releases from southern Sierra Nevada reservoirs were
mg/L
120
160
200
240
280
320
360
400
TDS
mg/L
10
20
30
40
50
60
70
80
90
100
Chloride
mg/L
10
30
50
70
90
110
Sulfate
mg/L (as CaCO3)
40
60
80
100
120
140
160
180
200
Pyramid Lake
Castaic Lake
Silverwood Lake
Lake Perris
.
Pyramid Lake
Castaic Lake
Silverwood Lake
Lake Perris
Hardness
1999
1998
mg/L
0.08
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
Bromide
mg/L
2
3
4
5
6
7
8
9
TOC
micro g/L
300
320
340
360
380
400
Pyramid Lake
Castaic Lake
Silverwood Lake
Lake Perris
.
Pyramid Lake
Castaic Lake
Silverwood Lake
Lake Perris
TTHMFP
1998
1999
Min-Max
Mean
Water Quality Assessment of the State Water Project, 1998-99
5 Executive Summary
diverted into the Kern River Intertie and Cross Valley Canal (and eventually the Aqueduct) to alleviate
flooding in the San Joaquin Valley. The flood event lasted 96 days from April 3 to July 8, 1998. With few
exceptions, both inflows exhibited low TDS ranging from 102 to 124 mg/L. Suspended solids were
moderate, ranging from 28 to 88 mg/L. The inflows composed almost all water pumped south during the
event and Aqueduct water quality reflected that. There were no inflows in 1999.
Natural Inflow to Project Lakes in Southern California
Pyramid Lake. Natural inflow to Pyramid Lake totaled 133,135 af in 1998 and 16,493 af in 1999,
amounting to 52 and 5 percent, respectively, of all Project/non-Project inflows. Piru Creek drains a
372 square-mile watershed and is the largest natural source to the lake. The creek has elevated salt levels
and a sulfate concentration that is eight times greater than Project water and a chloride concentration that
is nine times less. Nineteen ninety-eight was a high inflow year and lake mineralogy shifted to reflect
these concentration differences. The bulk of the 1998 inflow occurred in February. Soon after, sulfate and
hardness in the lake increased relative to chloride and stayed elevated through February 1999. These
mineral shifts indicate that Piru Creek can have a major influence on the lake’s water quality. In 1995,
Piru Creek accounted for 35 percent of all inflows and 58 percent of the TDS load, making it the single
largest source of salt to the lake in wet years.
Castaic Lake. Natural inflow to Castaic Lake totaled 126,224 af in 1998 and 10,220 af in 1999,
amounting to 41 and 3 percent, respectively, of all Project/non-Project inflows. Six watersheds drain to
the 323,702 af lake, ranging in size from 2.7 to 41.7 square miles. Assessing the effects of natural inflow
is problematic due to pump-back from Elderberry Forebay. Water in the forebay can be pumped back into
Pyramid Lake for energy management purposes, and about half of all natural inflow drains to this
forebay. Similar to Pyramid Lake, sulfate and hardness increased relative to chloride in early 1998 but the
increase continued through 1999. The mineral shift was likely due to Pyramid Lake releases.
Silverwood Lake. Natural inflow to Silverwood Lake totaled 41,730 af in 1998 and 2,291 af in 1999,
amounting to 11 and 0.5 percent, respectively, of all Project/non-Project inflows. Miller and Cleghorn
creeks are the two largest streams that, combined, drain about 60 square miles of watershed surrounding
the lake. The salinity of these streams is usually lower than Project water. High inflows during the first
few months of 1998 coincided with a 97 to 136 mg/L decrease in TDS in the lake and at Devil Canyon
Afterbay. TDS remained low into spring and summer because of East Branch contributions from low-
salinity Delta and Kern River waters.
Water Quality Assessment of the State Water Project, 1998-99
7 Introduction
II. Introduction
Objectives
Within the Division of Operations and Maintenance, five field divisions and the Water Quality Section
are responsible for monitoring and assessing water quality in the State Water Project. The objectives are
to:
1.
assess the influence of hydrological conditions and water operations on Project water
quality;
2.
document long-term changes in Project water quality;
3.
provide Project contractors with water quality data to assess water treatment plant
operational needs;
4.
identify, monitor, and respond to water quality emergencies and determine impacts to the
Project;
5.
assess the relative quality of Project water by comparing concentration data to Article 19
objectives or Department of Health Services Drinking Water Standards; and
6.
assess water quality issues of particular concern through special investigations.
Monitoring Strategy
Water quality samples are routinely collected at 29 stations throughout the State Water Project
(Table A-1, Appendix A). Stations are distributed over a distance of more than 500 miles, from the upper
Feather River watershed in Plumas County to Lake Perris in Riverside County (Figure A-1 and Plates 1 to
5). Monitoring is conducted in the Feather River watershed, North Bay Aqueduct, South Bay Aqueduct,
Coastal Branch, California Aqueduct—including its four terminus lakes—and the Central Valley
Project’s Delta-Mendota Canal.
Grab samples are collected by staff from the Oroville, Delta, San Luis, San Joaquin, and Southern field
divisions on a monthly, quarterly, or as needed basis. Subsurface samples are collected from a depth of
between 1 to 9 feet at both channel and lake stations. Samples are transported to the Department’s Bryte
Chemical Laboratory within 24 hours of collection. Laboratory analyses have included inorganic and
organic parameters such as major minerals, metals, and pesticides (Table A-1). Details of field and lab
methods are presented in Appendix A, Methods.
Automated water quality monitoring stations measure conventional parameters such as conductivity,
temperature, or turbidity at 20 locations throughout the Project (Table A-2, Figure A-1 and Plates 1 to 5).
Data are logged on an hourly basis and daily averages are uploaded to O&M’s Water Quality Homepage
at
http://wwwomwq.water.ca.gov
. Data are used to define hourly or daily water quality trends.
Water Quality Standards and Objectives
Primary Drinking Water Standards or Maximum Contaminant Levels are the maximum permissible levels
in a public drinking water supply. These standards must be met in finished drinking water (potable water)
to protect human health. Since raw water in the Project is not required to meet MCL standards,
comparisons are made with Project data to provide a relative indication of raw water quality.
Secondary Drinking Water Standards are consumer acceptance standards designed to protect taste, odor,
color, and other aesthetic aspects of drinking water that are not considered health risks. Similar to Primary
Water Quality Assessment of the State Water Project, 1998-99
Introduction
8
MCLs, they are used for comparison purposes only. Primary and Secondary MCLs are presented in
Appendix B, Water Quality Standards and Objectives.
Article 19 objectives are included as standard provisions in the Department’s water supply contracts.
They require the collection and analysis of water quality samples in the Project and the compilation of
records. Article 19(a) states:
“It shall be the objective of the State and the State shall take all reasonable measures to make available, at
all delivery structures for the delivery of Project water to the District, Project water of such quality that the
following constituents do not exceed the concentrations stated.”
These objectives are listed along with MCLs in Appendix B.
Water Quality Assessment of the State Water Project, 1998-99
9 Annual and Seasonal Trends
III. Annual and Seasonal Trends
This chapter describes general water quality trends in the State Water Project during 1998-99. Annual
summaries for each station were presented in box and whisker plots or tables. Box and whisker plots
show the median, 20-80th percentile range, non-extreme minimums/maximums, and values that were
1.5 times outside of the 20-80th percentile range. The latter values usually highlighted specific events that
were detailed in Chapter IV.
Water quality parameters are presented in the following order: conventional parameters (e.g., pH,
hardness) and major minerals, minor elements, trihalomethane precursors and formation potential, and
organic chemicals.
Conventional Parameters and Major Minerals
Conventional parameters include conductivity, hardness, lab pH, suspended solids, suspended volatile
solids, field temperature, total dissolved solids, and turbidity. Major minerals include the cations calcium,
magnesium, and sodium, and the anions bicarbonate (alkalinity), chloride, nitrate, and sulfate.
Feather River Watershed
All data from Project stations in the Feather River watershed were below the Article 19 objectives or
MCLs for finished drinking (Tables 3-1). The cations calcium, magnesium, and sodium were less than
10 mg/L at all stations. Bicarbonate dominated the anionic composition while chloride, nitrate, and sulfate
were near or below their respective reporting limits.
North and South Bay Aqueducts and San Luis Reservoir
On the North Bay Aqueduct, all data were below the MCLs for finished drinking water or Article 19
objectives. At Barker Slough Pumping Plant, the median and range of most water quality constituents
were similar between years (Figures 3-1 and 3-2). TDS ranged from 90 to 300 mg/L and was highest from
late spring to early summer of both years (Figure 3-3). Similar trends were observed for sulfate, chloride,
and hardness (Figure 3-4). Turbidity at Barker Slough Pumping Plant ranged between 27 and 256 NTU in
1998 and between 18 and 222 NTU in 1999. During both years, levels were highest during the winter
months when rainfall runoff transports sediment from the upstream watershed.
On the South Bay Aqueduct, stations include Check 7, Santa Clara Terminal Tank, and Lake Del Valle
(usually reservoir releases). With the exception of three samples from Lake Del Valle and one from
Check 7, all data were below the Article 19 objectives or MCLs for finished drinking water
(Figures 3-1 and 3-2). Hardness was above the Article 19 Objective of 180 mg/L in five of eight samples
collected from Lake Del Valle during the 2-year period (Figure 3-4). Turbidity in the reservoir reached
65 NTU in March 1998 and coincided with natural inflows from Arroyo Del Valle totaling 65,000 af. One
sample collected at Check 7 on the South Bay Aqueduct contained 151 mg/L of chloride, above the
Article 19 Objective of 110 mg/L (Figure 3-4). The same sample contained sodium over the Article 19
Objective. The high chloride and sodium levels were detected in December 1999 when salinity intrusion
affected all south Delta exports.
Salinity trends on the South Bay Aqueduct at Check 7 were similar to those at Banks Pumping Plant on
the California Aqueduct. Median TDS at Check 7 was 185 mg/L (range 85 to 386 mg/L) compared to
179 mg/L at Banks Pumping Plant (range 85 to 388 mg/L) (Figure 3-3). Similarities were also observed
for chloride, sulfate, and hardness. Regression correlations for these parameters between stations ranged
from 0.96 for sulfate to 0.99 for chloride during 1998-99.
Water Quality Assessment of the State Water Project, 1998-99
Annual and Seasonal Trends
10
Table 3-1
Conventional Parameters and Major Minerals in the Feather River Watershed, 1998-99
1998
1999
# of
# of
Parameter
Station Name
I.D. #
Median
Low
High
Samples
Median
Low
High
Samples
Conductivity
Antelope Lake
AN001000
72
1
(Specific Conductance)
Frenchman Lake
FR001000
92
1
µ
S/cm
Lake Davis
LD001000
58
1
Thermalito Forebay
TF001000
72
68
81
4
78
78
80
4
Thermalito Afterbay
TA001000
73
67
89
12
77
76
81
10
Hardness
Antelope Lake
AN001000
26
1
mg/L as CaCO3
Frenchman Lake
FR001000
39
1
Lake Davis
LD001000
23
1
Thermalito Forebay
TF001000
30
29
32
4
32
32
4
Thermalito Afterbay
TA001000
30
27
36
12
32
30
33
10
pH, Lab
Antelope Lake
AN001000
7.2
1
Frenchman Lake
FR001000
7.0
1
Lake Davis
LD001000
6.7
1
Thermalito Forebay
TF001000
7.2
6.8
7.2
4
6.6
6.3
7.4
4
Thermalito Afterbay
TA001000
7.2
6.9
7.4
12
6.8
6.6
7.1
10
Suspended Solids, mg/L
Thermalito Afterbay
TA001000
4
3
6
3
1
<1
1
3
Suspended Volatile Solids
mg/L
Thermalito Afterbay
TA001000
4
1
6
6
1
1
2
6
Temperature
Antelope Lake
AN001000
18.9
1
Degrees C
Frenchman Lake
FR001000
15.5
1
Lake Davis
LD001000
17.8
13
24
6
17.3
11.4
20.6
8
Lake Oroville
OR001000
17.8
14.4
27.2
6
22.2
15.6
23.9
7
Thermalito Forebay
TF001000
15.6
7.8
20.6
11
15.6
7.8
20.6
12
Thermalito Afterbay
TA001000
10.0
8.9
12.2
4
11.7
8.9
13.9
4
Total Dissolved Solids
Antelope Lake
AN001000
65
1
mg/L
Frenchman Lake
FR001000
64
1
Lake Davis
LD001000
41
1
Thermalito Forebay
TF001000
44
43
54
4
55
50
63
4
Thermalito Afterbay
TA001000
54
44
63
10
49
38
69
10
Turbidity, NTU
Antelope Lake
AN001000
3
1
Frenchman Lake
FR001000
3
1
Lake Davis
LD001000
2
1
Thermalito Forebay
TF001000
4
5
2
1
1
9
4
Thermalito Afterbay
TA001000
5
2
9
11
3
2
4
10
Calcium
Antelope Lake
AN001000
7.0
1
mg/L
Frenchman Lake
FR001000
9.0
1
Lake Davis
LD001000
6.0
1
Thermalito Forebay
TF001000
7.0
7.0
8.0
4
8.0
7.7
8.0
4
Thermalito Afterbay
TA001000
7.0
6.6
8.0
12
8.0
6.8
8.0
10
Magnesium
Antelope Lake
AN001000
2.0
1
mg/L
Frenchman Lake
FR001000
4.0
1
Lake Davis
LD001000
2.0
1
Thermalito Forebay
TF001000
3.0
2.8
3.0
4
3.0
3.0
3.1
4
Thermalito Afterbay
TA001000
2.9
2.7
4.0
12
3.0
3.0
3.3
10
Sodium
Antelope Lake
AN001000
3
1
mg/L
Frenchman Lake
FR001000
5
1
Lake Davis
LD001000
3
1
Thermalito Forebay
TF001000
3
2.8
3
4 3
3
3
3.3
4
Thermalito Afterbay
TA001000
3
2.6
4
12
3
3
4
10
Bicarbonate
Antelope Lake
AN001000
41
1
(Alkalinity)
Frenchman Lake
FR001000
50
1
mg/L as CaCO3
Lake Davis
LD001000
31
1
Thermalito Forebay
TF001000
32
32
39
4
38
36
43
4
Thermalito Afterbay
TA001000
33
32
39
12
38
36
40
10
Chloride
Antelope Lake
AN001000
<1.0
1
mg/L
Frenchman Lake
FR001000
<1.0
1
Lake Davis
LD001000
<1.0
1
Thermalito Forebay
TF001000
<1.0
<1.0
1.0
4
<1.0
<1.0
1.0
4
Thermalito Afterbay
TA001000
<1.0
<1.0
1.0
12
1.0
<1.0
1.0
10
Nitrate
Antelope Lake
AN001000
<0.1
1
mg/L as NO3
Frenchman Lake
FR001000
<0.1
1
Lake Davis
LD001000
<0.1
1
Thermalito Forebay
TF001000
<0.1
<0.1
0.2
4
<0.1
<0.1
0.2
4
Thermalito Afterbay
TA001000
<0.1
<0.1
0.2
12
<0.1
<0.1
0.1
10
Sulfate
Antelope Lake
AN001000
<1.0
1
mg/L
Frenchman Lake
FR001000
1
1
Lake Davis
LD001000
<1.0
1
Thermalito Forebay
TF001000
2
<1
2
4
2
2
3
4
Thermalito Afterbay
TA001000
2
<1
2
12
2
<1
3
10
Water Quality Assessment of the State Water Project, 1998-99
11 Annual and Seasonal Trends
Figure 3-1
Conventional Parameters in the North and South Bay Aqueducts and San Luis Reservoir,
1998-99
micro S/cm
100
200
300
400
500
600
700
800
Conductivity
Non-Extreme Min-Max
Median
20-80%
1.5x outside 20-80%
mg/L (as CaC03)
20
60
100
140
180
220
Hardness
pH Units
6.4
6.8
7.2
7.6
8.0
8.4
8.8
pH, Lab
mg/L
0
20
40
60
80
100
120
140
NBA, Barker Sl. PP
NBA,Cordelia Forebay
SBA, DelValle Outlet
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
.
NBA, Barker Sl. PP
NBA,Cordelia Forebay
SBA, DelValle Outlet
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
1998
1999
Suspended Solids
Water Quality Assessment of the State Water Project, 1998-99
Annual and Seasonal Trends
12
Figure 3-1 (Con’t)
Conventional Parameters in the North and South Bay Aqueducts and San Luis Reservoir,
1998-99
mg/L
0
4
8
12
16
20
24
Non-Extreme Min-Max
Median
20-80%
1.5x outside 20-80%
Suspended
Volatile Solids
Degrees C
4
8
12
16
20
24
28
Temperature
mg/L
50
100
150
200
250
300
350
400
450
Total Dissolved Solids
NTU
0
40
80
120
160
200
240
280
NBA, Barker Sl. PP
NBA,Cordelia Forebay
SBA, DelValle Outlet
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
.
NBA, Barker Sl. PP
NBA,Cordelia Forebay
SBA, DelValle Outlet
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
Turbidity
1998
1999
Water Quality Assessment of the State Water Project, 1998-99
13 Annual and Seasonal Trends
Figure 3-2
Major Minerals in the North and South Bay Aqueducts and San Luis Reservoir, 1998-99
mg/L as CaCO3
20
40
60
80
100
120
140
160
180
200
Bicarbonate (Alkalinity)
mg/L
0
10
20
30
40
50
Non-Extreme Min-Max
Median
20-80%
1.5x outside 20-80%
Calcium
mg/L
0
40
80
120
160
Chloride
mg/L
2
6
10
14
18
22
26
30
NBA, Barker Sl. PP
NBA,Cordelia Forebay
SBA, DelValle Outlet
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
.
NBA, Barker Sl. PP
NBA,Cordelia Forebay
SBA, DelValle Outlet
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
Magnesium
1999
1998
Water Quality Assessment of the State Water Project, 1998-99
Annual and Seasonal Trends
14
Figure 3-2 (Con’t)
Major Minerals in the North and South Bay Aqueducts and San Luis Reservoir, 1998-99
All data from San Luis Reservoir were below the Article 19 objectives or MCLs for finished drinking
water (Figures 3-1 and 3-2). Turbidity in the reservoir remained largely below 5 NTU and TDS ranged
between 226 and 295 mg/L (Figure 3-3). Chloride declined from 76 mg/L in August 1998 to 65 mg/L in
October (Figure 3-4). Reservoir filling was initiated in September and dilution from low-salinity Delta
water coincided with the decline. Chloride (and salinity in general) has been steadily declining in San
Luis Reservoir since 1991 when the concentration peaked at 149 mg/L (TDS = 420 mg/L). The higher
levels earlier in the decade were due to lake filling during the 1989-92 drought. Reservoir filling is
greatest during fall and winter when salinity intrusion in the Delta is most probable.
mg/L
0
2
4
6
8
Nitrate
Non-Extreme Min-Max
Median
20-80%
1.5x outside 20-80%
mg/L
0
20
40
60
80
100
Sodium
mg/L
0
10
20
30
40
50
60
70
NBA, Barker Sl. PP
NBA,Cordelia Forebay
SBA, DelValle Outlet
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
.
NBA, Barker Sl. PP
NBA,Cordelia Forebay
SBA, DelValle Outlet
SBA, Check 7
SBA, Terminal Tank
San Luis Reservoir
1998
1999
Sulfate
Water Quality Assessment of the State Water Project, 1998-99
15 Annual and Seasonal Trends
Figure 3-3
Monthly TDS and Turbidity in the North and South Bay Aqueducts and
San Luis Reservoir
SBA, Santa Clara Terminal Tank
50
100
150
200
250
300
350
400
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
TDS, mg/L
0
5
10
15
20
25
30
35
Turbidity,NTU
San Luis Reservoir
50
100
150
200
250
300
350
400
Jan-98
Feb-98
Mar-98
Apr-98
May-98
Jun-98
Jul-98
Aug-98
Sep-98
Oct-98
Nov-98
Dec-98
Jan-99
Feb-99
Mar-99
Apr-99
May-99
Jun-99
Jul-99
Aug-99
Sep-99
Oct-99
Nov-99
Dec-99
TDS, mg/L
0
5
10
15
20
25
30
35
Turbidity,NTU
NBA, Barker Slough Pumping Plant
50
100
150
200
250
300
350
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
TDS, mg/L
0
50
100
150
200
250
Turbidity,NTU
Total Dissolved Solids
Turbidity
SBA, Check 7
50
100
150
200
250
300
350
400
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
TDS, mg/L
0
5
10
15
20
25
30
35
Turbidity,NTU
SBA, Del Valle Reservoir Outlet
50
100
150
200
250
300
350
400
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
TDS, mg/L
0
5
10
15
20
25
30
35
Turbidity,NTU
37
65
Water Quality Assessment of the State Water Project, 1998-99
Annual and Seasonal Trends
16
Figure 3-4
Monthly Sulfate, Chloride, and Hardness in the North and South Bay Aqueducts and
San Luis Reservoir
NBA, Barker Slough Pumping Plant
0
20
40
60
80
100
120
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
SO4 & Cl, mg/L
40
60
80
100
120
140
160
180
200
Hardness,mg/L
Sulfate (SO4)
Chloride (Cl)
Hardness (as CaCO3)
SBA, Santa Clara Terminal Tank
0
20
40
60
80
100
120
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
SO4 & Cl, mg/L
40
60
80
100
120
140
160
180
200
Hardness,mg/L
San Luis Reservoir
0
20
40
60
80
100
120
Jan-98
Feb-98
Mar-98
Apr-98
May-98
Jun-98
Jul-98
Aug-98
Sep-98
Oct-98
Nov-98
Dec-98
Jan-99
Feb-99
Mar-99
Apr-99
May-99
Jun-99
Jul-99
Aug-99
Sep-99
Oct-99
Nov-99
Dec-99
SO4 & Cl, mg/L
40
60
80
100
120
140
160
180
200
Hardness,mg/L
SBA, Del Valle Reservoir Outlet
0
20
40
60
80
100
120
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
SO4 & Cl, mg/L
40
60
80
100
120
140
160
180
200
Hardness,mg/L
SBA, Check 7
0
20
40
60
80
100
120
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
SO4 & Cl, mg/L
40
60
80
100
120
140
160
180
200
Hardness,mg/L
151
Water Quality Assessment of the State Water Project, 1998-99
17 Annual and Seasonal Trends
California Aqueduct and Coastal Branch
Most water quality parameters in the California Aqueduct and Coastal Branch were below MCLs for
finished drinking water or Article 19 objectives (Figures 3-5 and 3-6). The exceptions were TDS,
chloride, sulfate, and hardness. In February 1998, TDS at Check 21 was 593 mg/L, above the
Recommended Secondary MCL for finished drinking of 500 mg/L (Figure 3-7). In the same sample,
sulfate was above the Secondary MCL of 250 mg/L and hardness was above the Article 19 Objective of
180 mg/L (Figure 3-8). These high levels were caused by floodwater inflow to the San Luis Canal (see
Non-Project Inflows). Chloride was detected above the Article 19 Objective of 110 mg/L in December
1999 at Clifton Court Forebay (120-126 mg/L) and Banks Pumping Plant (151 mg/L). Sodium was above
the Article 19 Objective in the same samples. The high chloride and sodium levels were the result of
salinity intrusion in the south Delta that affected all exports.
