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100-Year Hydrology Modernization


The design of levees is fundamentally related to the 100-year water levels experienced for any given stretch of levee. Consequently, precise determination of 100-year water levels is a critical data need for accurate assessment of the level of protection actually being provided. Determination of 100-year water levels utilizes data from the historic water level data records collected at gauges located throughout the Delta. Systematic analysis and correction (where needed) of these historic records is needed prior to extracting historic high water levels.

100-Year Hydrology Modernization (PDF, 3 MB)


Project Description

DWR is conducting a review of the historic water level gauge data at 41 locations spread throughout the Delta & Suisun Marsh. The data will be corrected for measurement errors, datum conversion issues, data gaps, and other anomalies as required. Once the data are corrected, the high water stages from the entire historic record will be extracted and produced to potentially support updated determination of 100-year flood elevations throughout the Delta.

Below is a list of gauges where this work will be performed.

No. Station Name
B91510 Yolo Bypass at Liberty Island (Yolo Bypass)
B91560 Yolo Bypass near Lisbon
B94175 Mokelumne River near Thornton
B95260 Discovery Bay at Indian Slough
B95261 Discovery Bay at Discovery Bay Blvd.
B95400 Old River at Head
B95420 Tom Paine Slough above Mouth
B95421 Tom Paine Slough above Intake Structure
B95425 Tom Paine Slough at Pescadera Pump Plant 6
B95530 Middle River at Howard Road Bridge
B95765 San Joaquin River below Old River, near Lathrop
A02100 Sacramento River at Sacramento ('I' Street)
B94133 Mokelumne River, North Fork, below Snodgrass
B91650 Sacramento River at Walnut Grove_Stage
B94150 Mokelumne River, South Fork, at New Hope
B91212 Sacramento River at Rio Vista
B94100 Georgiana Slough at Mokelumne River
B95060 Threemile Slough at San Joaquin River
B95100 San Joaquin River at San Andreas
B95580 San Joaquin River at Venice Island
B95250 Old River at Bacon Island
B95460 Middle River at Bacon Island
B95468 Middle River at Middle River
B95020 San Joaquin River at Antioch
B95620 San Joaquin River at Rindge Pump
B95218 Rock Slough at Contra Costa Canal
B95660 Stockton Ship Channel at Burn's Cutoff
B95270 Old River near Byron
B95500 Middle River at Borden Highway (Hwy 4)
B95740 San Joaquin River at Brandt Bridge
B95540 Middle River at Mowry Bridge
B95340 Old River at Clifton Court Ferry
B95530 Middle River at Howard Road Bridge
B95310 Grantline Canal above the Barrier
B95300 Grantline Canal at Tracy Road
B95820 San Joaquin River @ Mossdale Bridge
B95380 Old River at Tracy Road Bridge
B95503 Middle River at Tracy Road Bridge
B95365 Old River near DMC (below dam)
B95366 Old River near DMC (above dam)
B94175 Miner Slough