Nine Decades of Salinity Observations in the San Francisco Bay and Delta: Modeling and Trend Evaluations
Abstract
Introduction
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Methods
Salinity Data Sources and Cleaning
Isohaline Calculations
Modeling Approach
Statistical Analyses
Results
Cleaned and Filled Salinity Data
Station name | Distance from golden gate (km) | Approximate period of record | Cleaned and filled data completeness | Specific conductance percentiles () | |||
---|---|---|---|---|---|---|---|
Count (days) | Missing (%) | 10% | 50% | 90% | |||
Bay stations | |||||||
Point Orient | 19.8 | February 1926–June 1971 | 13,976 | 16 | 20 | 27 | 29 |
Point Davis | 40.6 | February 1926–June 1971 | 14,802 | 11 | 7.0 | 20 | 27 |
Crockett | 44.6 | February 1926–June 1971 | 13,685 | 17 | 5.7 | 19 | 26 |
Benicia | 52.3 | February 1926–June 1971 | 13,706 | 17 | 3.6 | 16 | 24 |
Martinez | 52.6 | February 1926–June 1971 | 13,760 | 17 | 1.9 | 13 | 22 |
Bulls Head Point | 54.7 | February 1926–August 1957 | 9,007 | 22 | 1.9 | 15 | 25 |
West Suisun | 59.5 | October 1921–June 1971 | 13,410 | 26 | 0.7 | 9.7 | 21 |
Bay Point | 64.2 | October 1921–December 1968 | 11,174 | 35 | 0.5 | 9.3 | 22 |
Port Chicago | 66.0 | October 1921–June 1971 | 14,745 | 19 | 0.3 | 8.3 | 21 |
O and A Ferry | 74.8 | October 1921–June 1971 | 15,522 | 14 | 0.3 | 1.7 | 14 |
Lower Sacramento River stations | |||||||
Collinsville | 81.8 | October 1921–June 1971 | 15,751 | 13 | 0.2 | 0.4 | 8.9 |
Emmaton | 92.9 | October 1921–June 1971 | 15,185 | 16 | 0.2 | 0.3 | 2.0 |
Three Mile Slough Bridge | 96.6 | October 1921–June 1971 | 15,178 | 16 | 0.2 | 0.3 | 0.8 |
Rio Vista | 102.2 | September 1922–June 1971 | 14,408 | 19 | 0.1 | 0.2 | 0.3 |
Lower San Joaquin River stations | |||||||
Antioch | 88.4 | October 1921–June 1971 | 15,451 | 15 | 0.2 | 0.4 | 6.0 |
Antioch Bridge | 93.7 | October 1921–June 1971 | 14,760 | 19 | 0.3 | 0.3 | 1.8 |
Jersey Point | 98.8 | October 1921–June 1971 | 15,380 | 15 | 0.2 | 0.3 | 1.6 |
False River | 101.2 | October 1921–June 1971 | 13,883 | 24 | 0.2 | 0.2 | 0.8 |
Oulton Point | 108.1 | September 1952–June 1971 | 5,395 | 21 | 0.1 | 0.2 | 0.4 |
San Andreas Landing | 113.1 | September 1952–June 1971 | 5,395 | 21 | 0.1 | 0.2 | 0.3 |
Note: Statistics for the resulting cleaned and filled daily average Bulletin 23 specific conductance data are shown for key locations by river branch.
Station name | Distance from golden gate (km) | Approximate period of record | Cleaned and filled data completeness | Specific conductance range () | |||
---|---|---|---|---|---|---|---|
Count (days) | Missing (%) | 10% | 50% | 90% | |||
Bay stations | |||||||
Point San Pablo | 22 | January 1965–September 2012 | 16,839 | 3 | 25 | 38 | 44 |
Carquinez | 45.5 | January 1965–September 2012 | 17,010 | 2 | 12 | 27 | 36 |
Martinez | 54 | September 1995–September 2012 | 6,033 | 3 | 2.7 | 18 | 26 |
Martinez (USBR) | 55 | January 1965–April 1996 | 11,345 | 1 | 2.2 | 16 | 27 |
Port Chicago | 64 | January 1965–September 2012 | 17,389 | 0 | 0.3 | 9.3 | 20 |
Mallard Island | 75 | July 1964–September 2012 | 17,505 | 1 | 0.2 | 3.0 | 12 |
Lower Sacramento River stations | |||||||
Collinsville | 81 | July 1964–September 2012 | 16,985 | 4 | 0.2 | 1.0 | 7.7 |
Emmaton | 92 | July 1964–September 2012 | 17,420 | 1 | 0.1 | 0.2 | 2.2 |
Rio Vista | 101 | July 1964–September 2012 | 17,420 | 1 | 0.1 | 0.2 | 0.3 |
Lower San Joaquin River stations | |||||||
Pittsburg | 77 | January 1965–September 2012 | 17,405 | 0 | 0.2 | 2.3 | 10 |
Antioch | 85.8 | July 1964–September 2012 | 17,561 | 0 | 0.2 | 0.7 | 4.8 |
Blind Point | 92.9 | July 1964–September 2012 | 17,540 | 0 | 0.2 | 0.4 | 2.4 |
Jersey Point | 95.8 | July 1964–September 2012 | 17,388 | 1 | 0.2 | 0.3 | 1.7 |
Three Mile Slough at San Joaquin River | 100.4 | July 1964–September 2012 | 17,320 | 2 | 0.1 | 0.3 | 1.1 |
San Andreas Landing | 109.2 | July 1964–September 2012 | 17,526 | 0 | 0.1 | 0.2 | 0.3 |
Note: Statistics for the resulting cleaned and filled daily average CDEC specific conductance data are shown for key locations by river branch. CDEC = California Data Exchange Center; USBR = U.S. Bureau of Reclamation.
Interpolated and Model-Predicted X2 Position
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Other Model Predictions
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Isohaline Position Trend Analysis
Month | Full period 1922–2012 | Preproject period 1922–1967 | Postproject period 1968–2012 | ||||||
---|---|---|---|---|---|---|---|---|---|
Sample size | Sen’s slope median () | Test decision | Sample size | Sen’s slope median () | Test decision | Sample size | Sen’s slope median () | Test decision | |
January | 83 | 0.10 | Up | 39 | No trend | 44 | 0.23 | No trend | |
February | 82 | 0.09 | Up | 39 | No trend | 43 | 0.10 | No trend | |
March | 83 | 0.08 | Up | 40 | 0.09 | No trend | 43 | 0.02 | No trend |
April | 82 | 0.15 | Up | 39 | 0.19 | No trend | 43 | 0.01 | No trend |
May | 85 | 0.13 | Up | 40 | 0.13 | No trend | 45 | No trend | |
June | 85 | 0.10 | Up | 40 | 0.01 | No trend | 45 | No trend | |
July | 87 | No trend | 42 | No trend | 45 | No trend | |||
August | 86 | Down | 41 | Down | 45 | 0.06 | No trend | ||
September | 88 | Down | 43 | Down | 45 | 0.20 | Up | ||
October | 88 | 0.00 | No trend | 43 | Down | 45 | 0.28 | Up | |
November | 86 | 0.11 | Up | 41 | Down | 45 | 0.37 | Up | |
December | 85 | 0.13 | Up | 40 | Down | 45 | 0.37 | Up |
Note: Over the entire period of record, the test shows (1) statistically significant increases in X2 from November through June and (2) statistically significant decreases in X2 for August and September. Over the preproject period (1922–1967), there is no significant change in X2 from January through July and a statistically significant decrease in X2 from August through December. Over the postproject period (1968–2012), there is a nearly inverse response in trends, with a statistically significant increase in X2 from September through December. Results are reported as an upward trend (up), a downward trend (down), or no trend.
Month | Year type | ||||
---|---|---|---|---|---|
Critical | Dry | Below normal | Above normal | Wet | |
January | 7.6 (no trend) | 9.1 (up) | 6.4 (no trend) | (no trend) | 3.7 (no trend) |
February | 16.3 (up) | 10.4 (up) | 4.4 (up) | 0.7 (no trend) | 5.8 (up) |
March | 14.2 (up) | 7.4 (up) | 3.2 (no trend) | 0.9 (no trend) | 1.7 (no trend) |
April | 13.9 (up) | 9.1 (up) | 9.0 (up) | 7.2 (no trend) | 4.5 (no trend) |
May | 12.8 (up) | 9.1 (up) | 12.9 (up) | 2.4 (no trend) | 6.3 (up) |
June | 2.0 (no trend) | 5.5 (no trend) | 15.5 (up) | 1.0 (no trend) | 6.8 (up) |
July | (up) | (down) | 6.1 (up) | (down) | 1.7 (no trend) |
August | (down) | (down) | (no trend) | (down) | (down) |
September | (down) | (no trend) | (no trend) | (down) | (down) |
October | 1.9 (no trend) | 0.6 (no trend) | (no trend) | 6.1 (no trend) | 0.0 (no trend) |
November | 9.4 (up) | 6.9 (no trend) | 2.7 (no trend) | 15.4 (no trend) | 3.8 (no trend) |
December | 9.2 (up) | 8.6 (up) | 4.2 (no trend) | 11.8 (no trend) | 3.0 (no trend) |
Note: In general, dry and critical year postproject X2 was statistically significantly higher (i.e., upstream) in December through May and lower (i.e., downstream) in August and September. Wet year postproject X2 was statistically significantly higher in May and June and lower in August and September. Results are reported as a nonparametric estimate of the median of the difference (km) between a postproject X2 and a preproject X2, and significance is reported as an upward trend (up), a downward trend (down), or no trend.
Month | Salinity trend: 1922–2012 | X2 Trend: 1922–2012 | ||||
---|---|---|---|---|---|---|
Martinez | Port Chicago | Mallard Island | Collinsville | Emmaton | ||
January | No trend | No trend | Up | Up | No trend | No trend |
February | Up | Up | No trend | No trend | No trend | Up |
March | No trend | No trend | Up | No trend | No trend | No trend |
April | Up | Up | Up | Up | No trend | Up |
May | Up | Up | Up | Up | No trend | Up |
June | Up | Up | Up | Up | No trend | Up |
July | No trend | No trend | No trend | No trend | No trend | No trend |
August | Down | Down | Down | Down | Down | Down |
September | Down | Down | Down | Down | Down | Down |
October | No trend | No trend | No trend | No trend | No trend | No trend |
November | No trend | No trend | No trend | No trend | No trend | No trend |
December | Up | Up | Up | Up | Up | Up |
Note: Detected salinity and X2 trends are generally consistent. When a trend was detected in both the salinity and X2 time series, the trends are uniformly consistent. When a trend was not detected in the X2 time series, the salinity trends are generally consistent, with exceptions in January (Mallard Island and Collinsville) and March (Mallard Island). Results are reported as an upward trend (up), a downward trend (down), or no trend.