Water Resources Development and Protection [Proposition 8]

LA Law Library (LALaw) | November 4th, 1980

Water Right Decision 1485: Sacramento-San Joaquin Delta and Suisun Marsh

California State Water Resources Control Board (SWRCB) | August 16th, 1978

Water Rights Decision 1641 (D-1641)

California State Water Resources Control Board (SWRCB) | December 29th, 1999

This decision is part of the SWRCB’s implementation of the 1995 Bay-Delta Plan. Many of the objectives in the 1995 Bay-Delta Plan are best implemented by making changes

This decision is part of the SWRCB’s implementation of the 1995 Bay-Delta Plan. Many of the objectives in the 1995 Bay-Delta Plan are best implemented by making changes in the flow of water or in the operation of facilities that move water. Accordingly, this decision amends certain water rights by assigning responsibilities to the persons or entities holding those rights to help meet the objectives.

Water shortage risks from perennial crop expansion in California’s Central Valley

Environmental Research Letters (IOP) | October 15th, 2019

California’s Central Valley is one of the world’s most productive agricultural regions. Its high-value fruit, vegetable, and nut crops rely on surface water imports

California’s Central Valley is one of the world’s most productive agricultural regions. Its high-value fruit, vegetable, and nut crops rely on surface water imports from a vast network of reservoirs and canals as well as groundwater, which has been substantially overdrafted to support irrigation. The region has undergone a shift to perennial (tree and vine) crops in recent decades, which has increased water demand amid a series of severe droughts and emerging regulations on groundwater pumping. This study quantifies the expansion of perennial crops in the Tulare Lake Basin, the southern region of the Central Valley with limited natural water availability. A gridded crop type dataset is compiled on a 1-square mile spatial resolution from a historical database of pesticide permits over the period 1974–2016 and validated against aggregated county-level data. This spatial dataset is then analyzed by irrigation district, the primary spatial scale at which surface water supplies are determined, to identify trends in planting decisions and agricultural water demand over time. Perennial crop acreage has nearly tripled over this period, and currently accounts for roughly 60% of planted area and 80% of annual revenue. These trends show little relationship with water availability and have been driven primarily by market demand. From this data, we focus on the increasing minimum irrigation needs each year to sustain perennial crops. Results indicate that under a range of plausible future regulations on groundwater pumping ranging from 10% to 50%, water supplies may fail to consistently meet demands, increasing losses by up to 30% of annual revenues. More broadly, the datasets developed in this work will support the development of dynamic models of the integrated water-agriculture system under uncertain climate and regulatory changes to understand the combined impacts of water supply shortages and intensifying irrigation demand.

Water Surplus and Drought Management Update - Conditions as of 11/29/2022

Metropolitan Water District of Southern California (MWD) | December 13th, 2022

Water Temperature Differences by Plant Community and Location in Re-established Wetlands in the Sacramento– San Joaquin Delta, California, July 2005 to February 2008

U.S. Geological Survey (USGS) | ?

Rates of carbon storage in wetlands are determined by the balance of its inputs and losses, both of which are affected by environmental factors such as water temperature

Rates of carbon storage in wetlands are determined by the balance of its inputs and losses, both of which are affected by environmental factors such as water temperature and depth. In the autumn of 1997, the U.S. Geological Survey re-established two wetlands with different shallow water depths—about 25 and 55 centimeters deep—to investigate the potential to reverse subsidence of delta islands by preserving and accumulating organic substrates derived from plant biomass inputs over time. Because cooler water temperatures can slow decomposition rates and increase accretion of plant biomass, water temperature was recorded from July 2005 to February 2008 in the deeper of the two wetlands, where areas of emergent and submerged vegetation persisted throughout the study, to assess differences in water temperature between the two vegetation types. Water temperature was compared at three depths in the water column between areas of emergent and submerged vegetation and between areas near the water inflow and in the wetland interior in both vegetation types. The latter comparison was a way of evaluating the effect of the length of time water had resided in the wetland on water temperatures. There were statistically significant differences in water temperature at all depths between the two vegetation types. Overall, in areas of emergent marsh vegetation, the mean water temperature at the surface was 1.4 degrees Celsius (°C) less than it was in areas of submerged vegetation; however, when analyses accounted for the changes in temperature due to seasonal and diurnal cycles, differences in the mean water temperature between the vegetation types were even greater than this. For example, in the spring, the mean temperatures in areas of emergent marsh vegetation at the surface, midpoint, and near the sediment in the water column were 2.0, 2.3, and 2.1 °C less, respectively, than water temperatures in areas of submerged vegetation. When diurnal changes in temperature were accounted for by comparing temperatures in mid-afternoon (at 3 p.m.), water-temperature differences were even greater than the seasonal means indicated. In areas of emergent vegetation, the mean temperatures were cooler than temperatures in areas of submerged vegetation at the surface, the mid-point, and near the sediment in the water column by 3.9, 3.6, and 2.3 °C, respectively. Furthermore, from July 2005 through December 2006, water temperatures at the surface in the interior of the wetland were significantly cooler than in areas near the inflow supplying water from the San Joaquin River by 1.0 °C in areas of submerged vegetation and by 1.1 °C in areas of emergent vegetation.

Water Temperature Modeling Platform Mid-Term Review

Delta Stewardship Council (Delta Council) | October 21st, 2021

Water Wasted to the Sea?

University of California, Davis (UC Davis) | July 15th, 2017

Water Year 2018 Hydrology

Delta Stewardship Council (Delta Council) | November 26th, 2018

Water-Power with High Pressures and Wrought-Iron Water-Pipe

Scientific American | September 13th, 1884

For the purpose of supplying the placer mines in California with water, many ditches were built on the western slope of the Sierra Nevada, taking their source high up in

For the purpose of supplying the placer mines in California with water, many ditches were built on the western slope of the Sierra Nevada, taking their source high up in the mountains, and delivering the water on the tops of the foot hill ridges, at elevations from 1,000 to 3,000 feet above the great valley of California, formed by the Sacramento and San Joaquin rivers. In many cases, the mines for which these aqueducts were constructed have been exhausted or abandoned, and their water is now largely used for power for quartz ruining and milling, and for other purposes.