San Joaquin River

SB-72 The California Water Plan: long-term supply targets

State of California | September 8th, 2025

Existing law requires the Department of Water Resources to update every 5 years the plan for the orderly and coordinated control, protection, conservation, development, a

Existing law requires the Department of Water Resources to update every 5 years the plan for the orderly and coordinated control, protection, conservation, development, and use of the water resources of the state, which is known as “The California Water Plan.” Existing law requires the department to include a discussion of various strategies in the plan update, including, but not limited to, strategies relating to the development of new water storage facilities, water conservation, water recycling, desalination, conjunctive use, and water transfers, that may be pursued in order to meet the future needs of the state. Existing law requires the department to establish an advisory committee to assist the department in updating the plan. This bill would revise and recast certain provisions regarding The California Water Plan to, among other things, require the department to expand the membership of the advisory committee to include, among others, tribes, labor, and environmental justice interests. The bill would require the department, as part of the 2033 update to the plan, to update the interim planning target for 2050, as provided. The bill would require the target to consider the identified and future water needs for all beneficial uses, including, but not limited to, urban uses, agricultural uses, tribal uses, and the environment, and ensure safe drinking water for all Californians, among other things. The bill would require the plan to include specified components, including a discussion of the estimated costs, benefits, and impacts of any project type or action that is recommended by the department within the plan that could help achieve the water supply targets. The bill would require the department to report to the Legislature the amendments, supplements, and additions included in the updates of the plan, together with a summary of the department’s conclusions and recommendations, in the session in which the updated plan is issued. The bill would also require the department to conduct public workshops to give interested parties an opportunity to comment on the plan.

Scrutinizing the Delta Cross Channel

CALFED | June 1st, 2001

Sea level rise and the drivers of daily water levels in the Sacramento-San Joaquin Delta

Nature Portfolio (Springer Nature) | December 17th, 2023

Sea Level Rise in California

Public Policy Institute of California (PPIC) | February 29th, 2024

Seasonal variation in total water storage in California inferred from GPS observations of vertical land motion

American Geophysical Union (AGU) | March 12th, 2014

GPS is accurately recording vertical motion of Earth's surface in elastic response to seasonal changes in surface water storage in California. California's mountains subs

GPS is accurately recording vertical motion of Earth's surface in elastic response to seasonal changes in surface water storage in California. California's mountains subside up to 12 mm in the fall and winter due to the load of snow and rain and then rise an identical amount in the spring and summer when the snow melts, the rain runs off, and soil moisture evaporates. We invert the GPS observations of seasonal vertical motions to infer changes in equivalent water thickness. GPS resolves the distribution of change in total water across California's physiographic provinces at a resolution of 50 km, compared to 200 km resolution from the Gravity Recovery and Climate Experiment. The seasonal surface water thickness change is 0.6 m in the Sierra Nevada, Klamath, and southern Cascade Mountains and decreases sharply to about 0.1 m east into the Great Basin and west toward the Pacific coast. GPS provides an independent inference of change in total surface water, indicating water storage to be on average 50% larger than in the NLDAS‐Noah hydrology model, likely due to larger changes in snow and reservoir water than in the model.

Seasonality of Retreat Rate of a Wave-Exposed Marsh Edge

American Geophysical Union (AGU) | July 10th, 2024

Waves can cause destruction of marshlands when they collide with the boundary of the marsh area. We studied how the speed of marsh loss from waves can change between seas

Waves can cause destruction of marshlands when they collide with the boundary of the marsh area. We studied how the speed of marsh loss from waves can change between seasons with different climates. To do this we made five 3D models of a marsh in South San Francisco Bay over a single year and looked at their differences between summer/fall/winter/spring. We found fast marsh loss in the seasons where daily winds are common (spring/summer), and minor changes in seasons with storms but without daily winds (fall/winter). Across our entire marsh, we saw lots of variety in how much it was changing, including some addition (i.e., positive change) to the mudflats near the marsh in the fall/winter. When we compared the marsh loss over one year to what was lost between 2004 and 2019, the speeds were similar, so we believe our study period was similar to long‐term marsh dynamics. This work encourages incorporating different seasonal climates into expectations of how marshes evolve, and supports that we need to think about marshes and mudflats as connected in how they change over time.

Second Supplement to State Water Resources Board Bulletin No. 11, San Joaquin County Investigation, Basic Data, Calaveras Unit, 1955-56

California Department of Water Resources (DWR) | April 20th, 1957

Sediment Lithology and Borehole Erosion Testing, American and Sacramento Rivers, California

U.S. Geological Survey (USGS) | July 9th, 2020

A field investigation intended to measure the potential for erosion of sediments beside the American and Sacramento Rivers near Sacramento, California, is described. The

A field investigation intended to measure the potential for erosion of sediments beside the American and Sacramento Rivers near Sacramento, California, is described. The study featured two primary components: (1) drilling and soil sampling to reveal lithology, down to depths matching the local river thalweg, where possible, and (2) borehole erosion tests (BETs) as described by Briaud and others (2017) at many of the same locations. The latter test involved drilling a vertical hole, measuring its diameter profile, inserting a hollow drilling rod to almost the bottom of the hole, and pumping fluid through the drilling rod at a known discharge for a chosen time interval. The hole was then resurveyed to establish an erosion rate (change in borehole radius divided by duration of flow event) as a function of depth, and the test was repeated. This test was performed with water as the erosive fluid at 12 locations, with 1 test repeated with drilling mud. Lithology holes were drilled at these same locations and an additional five locations. Drilling operations took place on river left and river right on the American River and river left (left bank, when looking downstream) on the Sacramento River.

Sediment Transport in Two Tributaries to the San Joaquin River Immediately Below Friant Dam—Cottonwood Creek and Little Dry Creek, California

U.S. Geological Survey (USGS) | May 2nd, 2023

Two tributaries to the greater San Joaquin River watershed, Cottonwood and Little Dry Creeks, in California’s Central Valley, were assessed for sediment and streamflow

Two tributaries to the greater San Joaquin River watershed, Cottonwood and Little Dry Creeks, in California’s Central Valley, were assessed for sediment and streamflow dynamics between October 1, 2011, and September 30, 2019. The two systems deliver sediment to the San Joaquin River below Friant Dam, California. Dams create downstream discontinuities in streamflow and sediment transport and therefore influence fish habitat and sediment dynamics. Because these two creeks are directly downriver from Friant Dam, they become the most upstream source of sediment to the San Joaquin River below Friant Dam. The quality and quantity of spawning habitat for fish in the gravel-bedded reach of the San Joaquin River relies on a range of bed material particle size suitable for redd structure. The effects of coarse-sand to fine-gravel supply on salmonid habitat depends primarily on the size of the sediment and the timing of its addition from tributaries to the San Joaquin River; thus, understanding the timing, quantity, and size of sediment supplied from these two tributaries is critical to the management of ecological and biological sustainability. Streamflow from Cottonwood and Little Dry Creeks, along with streamflow from the San Joaquin River below Friant Dam, were compared to continuously measured water-surface elevations to quantify the timing and direction of streamflow. Suspended-sediment samples were collected with multiple automatic samplers and analyzed for concentration and grain-size distribution. Measured suspended-sediment concentrations and streamflows were used to develop sediment rating curves and compute continuous estimates of suspended-sediment load for each tributary. Satellite imagery was used to qualify spatial and temporal dynamics through the lower watersheds and support more quantitative sediment-load estimates. Computed annual sediment loads ranged from 1.32x101 to 2.68x104 metric tons for Little Dry Creek and 9.82 to 1.98x103 metric tons for Cottonwood Creek. Sediment loads computed during the study period for both watersheds show that annual loads were highest during water year 2017 (October 1, 2016, to September 30, 2017). Sediment transport primarily occurred between the months of January and March. In both tributaries, grain-size distributions of suspended sediment were predominantly coarse-sized sand and were finer than the remnant bed material. Both creeks demonstrate backwater effects from the San Joaquin River, but the more tortuous stream channel and historical mining pits within Little Dry Creek provide more capacity for sediment storage compared to the less complex stream network of Cottonwood Creek. Because loads were computed based on upstream streamgages and not at the confluence of each tributary to the San Joaquin River, annual load estimates do not represent direct flux into the San Joaquin River; instead, these results indicated that in Little Dry Creek, particularly, the lowest portion of the watershed stores sediment before it reaches the San Joaquin River.

Senate Bill No. 1157

State of California | September 28th, 2022