River Conditions Metadata

SacPAS Process

Data for the SacPAS River Conditions dataset primarily comes from California Data Exchange Center (CDEC), CDWR and USGS Water Data for California, NWIS, USGS. The past 20 days of CDEC data are retrieved every day and then filtered by our CDEC Bounds Filter. Every year in December, we retrieve the full CDEC dataset and replace data in the event of corrections. For USGS, the past 1 year of data are retrieved daily with no filtering applied by SacPAS. If data is changed or removed by USGS, the most recent version of the data is loaded into SacPAS. It is expected that the rolling 1 year window covers the period of provisional data (subject to revision) to approved data (approved for publication -- processing and review completed) by USGS. Every year in December, we retrieve the full USGS dataset and replace data in the event of historical corrections.

• Fremont Weir: On October 3, 2016, the California Department of Water Resources (DWR) changed the reporting of river stage data collected at 5 locations in the lower Sacramento River area from their previous datum, either National Geodetic Vertical Datum 1929 (NGVD29) or United Stated Engineering Datum (USED) to the North American Vertical Datum 1988 (NAVD88) standard.
• Moulton, Colusa, Tisdale weirs: On October 1, 2019, the California Department of Water Resources (DWR) changed the reporting of river stage data collected at 21 locations in the upper Sacramento River and Feather River area from their previous datum, either National Geodetic Vertical Datum 1929 (NGVD29), United States Engineering Datum (USED), or Local Datum to the North American Vertical Datum 1988 (NAVD88) standard.
• MLW River Stage: Data recorded above minimum, 75.7 ft
• CLW River Stage: Data recorded above minimum, 60.4 ft
• TIS River Stage: Data recorded above minimum, 43.6 ft
• I:E Ratio = VNS Flow / ((CLC-BBI)+TRP Pumping Discharge)
• CVP+SWP Exports = HRO Pumping Discharge + TRP Pumping Discharge
• San Luis Reservoir Storage = LUS State + SLF Federal
• OMR Index calculated by SacPAS. For more information, see OMR Tidally Filtered Flow and Index Calculations as performed by SacPAS.
• USGS Tidally Filtered OMR = Tidally Filtered Flow at USGS 11312676 (Middle River) + 11313405 (Old River)

CDEC Bounds Filter

Appropriate data visualizations and modeling efforts in the Sacramento Basin depend on observational inputs of hydrosystem parameters. In order to properly inform, these parameter values must be constrained to real-world values. As a secondary data site, the California Data Exchange Center (CDEC) passes data unchanged from the original sources. Data errors can enter the system by a number of ways including sensor failure, transcription errors and recording errors. In order for data visualization and modeling projects to provide useful information, these errors must be identified and removed.

The first step in error correction is to remove the -9997, -9998, etc. values representing identified errors. Histograms of value distribution are then examined visually to identify outlier and spurious values. Each set of parameter values is limited as outlined below.

Remove Specific Invalid Values

• Values of -9997, -9998, -9999, -99999, or -999999.

Remove Non-Zero Minute Events

• Minute is not zero.

Remove Bad Oxygen Data

• Oxygen value is less than 0 or greater than 30.

Remove Temperature Values out of Bounds

• Water temperature is not between 32°F and 91°F.
• Water temperature is less than 34°F between February and November.
• VNS, water temperature exceeds 90°F.
• Water temperature is less than 26°F or greater than 90°F.
• Air temperature is less than 10°F or greater than 120°F.
• NFH: temperature is less than 31°F or greater than 85°F.
• LWS: temperature is less than 31°F or greater than 85°F.
• OBB: temperature is less than 35°F.
• AHZ: temperature exceeds 75°F.
• AWP: temperature is less than 39°F or greater than 84°F.
• AWB: temperature is less than 34°F or greater than 85°F.
• SHD: temperature is less than 34°F.
• KWK: temperature is less than 34°F or greater than 80°F.
• AND: temperature is less than 34°F or greater than 84°F.
• BSF: temperature is less than 33°F.
• RDB: temperature is less than 33°F.
• BND: temperature is less than 33°F or greater than 76°F.
• JLF: temperature is less than 35°F or greater than 70°F.
• CCR: temperature is less than 35°F.

Remove Specific Conductivity Values out of Bounds

• Specific conductivity value is greater than 999999.
• Specific conductivity value is less than 0.

Remove Elevation Values out of Bounds

• WHI: elevation is greater than 1225 or less than 1100.
• UNV: elevation is greater than 4900 or less than 4600.
• TUL: elevation is greater than 520.
• TAB: elevation is greater than 140 or less than 120.
• STG: elevation is greater than 848.
• SPC: elevation is less than 680.
• SLB: elevation is less than 1780.
• SHA: elevation is less than 800.
• ROR: elevation is greater than 10.
• RBL: elevation is less than 6530 or greater than 6650.
• ORO: elevation is less than 630 or greater than 905.
• NML: elevation is less than 700 or greater than 1100.
• NAT: elevation is less than 100 or greater than 150.
• MR2: elevation is less than 875 or greater than 900.
• MMW: elevation is less than 4800 or greater than 5000.
• LON: elevation is less than 6300 or greater than 6500.
• LGV: elevation is less than 5000 or greater than 5100.
• KES: elevation is less than 550 or greater than 600.
• JNC: elevation is less than 4300 or greater than 4470.
• INV: elevation is less than 1280 or greater than 1550.
• ICH: elevation is less than 5375 or greater than 5460.
• GLL: elevation is less than 5100 or greater than 5300.
• GDW: elevation is less than 340.
• FRD: elevation is less than 5500 or greater than 5608.
• FOL: elevation is less than 340 or greater than 470.
• ENG: elevation is less than 450 or greater than 550.
• DAV: elevation is less than 5700.
• Adjusts elevation values SIV by adding 7100 for values between 0 and 35.
• Adjusts elevation values CPL by adding 7894 for values between -1 and 70.
• CMI: elevation is less than 2800.
• CBR: elevation is less than 980 or greater than 1005.
• BLB: elevation is less than 350 or greater than 500.
• BIL: elevation is less than 6300.
• BHC: elevation is less than 2800.
• ALM: elevation is greater than 4550 or less than 4000.
• ANT: elevation is greater than 5025 or less than 4899.
• BER: elevation is greater than 456 or less than 360.

Remove Flow Values out of Bounds

• Flow value is less than -10000, except OMR.
• Flow value exceeds 10000000.
• FRE, ORO, NAT, ICH, ALM, BDT, P35, BBG, RUM, OBB, ORD, MCH, MCD, HMC, VON, and BRK: flow value is less than 0.
• ICH: flow value is less than -98.
• OBI and MDM: flow value is greater than 20000 or less than -20000.
• BDT: flow value exceeds 10000.
• SJL: flow value is less than -100 or greater than 200000.
• TSL: flow value exceeds 60000.
• SSS: flow value exceeds 10000000.
• NSL: flow value exceeds 20000.
• LIS: flow value exceeds 5000.
• LIB: flow value exceeds 20000.
• HWB: flow value exceeds 13000.
• SRV: flow value exceeds 400000.
• WSL: flow value is less than -260 or greater than 10000.
• VIN: flow value is less than -260 or greater than 200000.
• SUT: flow value is less than -26000 or greater than 20000.
• SDC: flow value is less than -20000 or greater than 60000.
• GSS: flow value is less than -10000 or greater than 20000.
• GES: flow value is less than -10000 or greater than 40000.
• DTO: flow value is less than -34000.
• DLC: flow value is less than -4000 or greater than 20000.
• FPT: flow value is less than -600000.
• FPT: flow value is less than 2000 and the timescale is daily.
• COL: flow value is less than -100.
• BLB: flow value exceeds 20000.
• BAT: flow value is less than -1.
• BCD: flow value exceeds 25000.
• BCK: flow value exceeds 19000.

Remove Storage Values out of Bounds

• WHI: storage value is less than or equal to 1000 or greater than 260000.
• STG: storage value is less than or equal to 0 or greater than 60000.
• SLB: storage value is less than or equal to 3000 or greater than 20000.
• SHA: storage value is less than or equal to 600000 or greater than 5000000.
• NAT: storage value is less than or equal to 1900 or greater than 10000.
• KES: storage value is less than 12000 or greater than 25000.
• ICH: storage value is less than 0 or greater than 50000.
• FRD: storage value is less than 0 or greater than 60000.
• FOL: storage value is less than 1000.
• ENG: storage value is less than 25000 or greater than 800000.
• CMI: storage value is less than 0 or greater than 99000.
• BUL: storage value is less than 30000 or greater than 1000000.
• BLB: storage value is less than 1450 or greater than 150000.
• BHC: storage value is less than 300 or greater than 1550.
• BER: storage value is less than 6000 or greater than 2000000.
• ANT: storage value is less than 250 or greater than 29000.

Remove Turbidity Values out of Bounds

• Turbidity value exceeds 1000.
• Turbidity value is less than 0.

Remove Stage Values out of Bounds

• Stage value exceeds 2720, except MVD.
• Stage value is less than -350.
• VNI, HST, DVD, and DLC: stage value is less than -100.
• VNI, HST, and DVD: stage value exceeds 100.
• TSL, RYI, ISB, MAL, LIR, BDL, DLC, LIS, and COL: stage value exceeds 700 or is less than -40.
• ANH: stage value is less than -20 or greater than 50.
• MEN, SJF, and SJN: stage value exceeds 20.
• JBP: stage value exceeds 25.
• LDC: stage value exceeds 15.
• BAT: stage value exceeds 30.
• SJS: stage value exceeds 80 or is less than 50.
• ELN and DGC: stage value exceeds 30.
• GRF: stage value exceeds 20 or is less than -10.
• IGO: stage value exceeds 20.
• OBB: stage value exceeds 46.
• CTK: stage value exceeds 15.
• DNB: stage value exceeds 50.
• VNS: stage value exceeds 42.
• SSH: stage value exceeds 105.
• LWS: stage value exceeds 28.
• BNF: stage value exceeds 18.
• AFO: stage value exceeds 50.
• NFH: stage value exceeds 30.
• SDC: stage value exceeds 25.