Age, growth, and trophic ecology of the Redeye Bass, an alien invader of California rivers

American Fisheries Society (AFS) | August 22nd, 2024

Aging dams, political instability, poor human decisions and climate change: recipe for human disaster

Nature Portfolio (Springer Nature) | January 16th, 2025

Agreement Between the United States of America and the State of California for Coordinated Operating Agreement for the Central Valley Project and the State Water Project

U.S. Bureau of Reclamation (USBR) | November 24th, 1986

The 1986 agreement between the Bureau of Reclamation and the Department of Water Resources for the coordinated operation of the Central Valley Project and the State Water

The 1986 agreement between the Bureau of Reclamation and the Department of Water Resources for the coordinated operation of the Central Valley Project and the State Water Project.

Agrichemicals in surface water and birth defects in the United States

Acta Paediatrica (Wiley) | March 6th, 2009

Objectives: To investigate if live births conceived in months when surface water agrichemicals are highest are at greater risk for birth defects. Methods: Monthly conc

Objectives: To investigate if live births conceived in months when surface water agrichemicals are highest are at greater risk for birth defects. Methods: Monthly concentrations during 1996–2002 of nitrates, atrazine and other pesticides were calculated using United States Geological Survey's National Water Quality Assessment data. Monthly United States birth defect rates were calculated for live births from 1996 to 2002 using United States Centers for Disease Control and Prevention natality data sets. Birth defect rates by month of last menstrual period (LMP) were then compared to pesticide/nitrate means using logistical regression models. Results: Mean concentrations of agrichemicals were highest in April–July. Total birth defects, and eleven of 22 birth defect subcategories, were more likely to occur in live births with LMPs between April and July. A significant association was found between the season of elevated agrichemicals and birth defects. Conclusion: Elevated concentrations of agrichemicals in surface water in April–July coincided with higher risk of birth defects in live births with LMPs April–July. While a causal link between agrichemicals and birth defects cannot be proven from this study an association might provide clues to common factors shared by both variables.

Agricultural Damages and Losses from ARkStorm Scenario Flooding in California

American Society of Civil Engineers (ASCE) | November 17th, 2016

Scientists designed the ARkStorm scenario to challenge the preparedness of California communities for widespread flooding with a historical precedence and increased l

Scientists designed the ARkStorm scenario to challenge the preparedness of California communities for widespread flooding with a historical precedence and increased likelihood under climate change. California is an important provider of vegetables, fruits, nuts, and other agricultural products to the nation. This study analyzes the agricultural damages and losses pertaining to annual crops, perennial crops, and livestock in California exposed to ARkStorm flooding. Statewide, flood damage is incurred on approximately 23% of annual crop acreage, 5% of perennial crop acreage, and 5% of livestock, e.g., dairy, feedlot, and poultry, acreage. The sum of field repair costs, forgone income, and product replacement costs span $3.7 and $7.1 billion (2009) for a range of inundation durations. Perennial crop loss estimates dominate, and the vulnerability of orchards and vineyards has likely increased with recent expansion. Crop reestablishment delays from levee repair and dewatering more than double annual crop losses in the delta islands, assuming the fragile system does not remain permanently flooded. The exposure of almost 200,000 dairy cows to ARkStorm flooding poses livestock evacuation challenges.

Agricultural Irrigation in This Drought: Where is the Water and Where Is It Going?

University of California Giannini Foundation of Agricultural Economics | May 14th, 2015

In the midst of its fourth year of drought, California now faces an estimated reduction in surface-water availability of 8.8 million acre-feet (maf) out of 29 maf in agri

In the midst of its fourth year of drought, California now faces an estimated reduction in surface-water availability of 8.8 million acre-feet (maf) out of 29 maf in agricultural applied water statewide. However, groundwater, the buffer water supply during drought, is replacing about 6.2 maf of surface water via additional pumping. This increased groundwater pumping is in addition to the 1.5 maf of annual average groundwater overdraft in the Central Valley. The net reduction of 2.6 maf in the total supply in 2015 may result in about 564,000 acres fallowed statewide, or about 120,000 more acres than last year's fallowing estimates.

Agricultural Land Stewardship (Resource Management Strategy)

California Department of Water Resources (DWR) | July 29th, 2016

This resource management strategy focuses primarily on private land in agriculture including cultivated land and rangeland. Agricultural land in California comprises abou

This resource management strategy focuses primarily on private land in agriculture including cultivated land and rangeland. Agricultural land in California comprises about 31.6 million acres (California Department of Conservation, Division of Land Resource Protection, Farmland Mapping and Monitoring Program 2008). About 12.4 million of these acres are cultivated, while the remaining 19.2 million acres are rangeland (California Department of Forestry and Fire Protection 2010). Agricultural systems in California are varied in the way resources are used, ranging from intensive conventional agriculture (irrigated crop cultivation) to more extensive systems such as livestock grazing, each with a different relationship to natural resources. They also affect and are affected by surface hydrology and groundwater recharge in different ways. Stewardship of this land requires constant balancing among natural constraints, market forces, and ever-changing social expectations. Institutions and policies have been developed in response to these challenges. Public investment in water infrastructure (reservoirs, canals, drains, levees, dykes) has been in the forefront of these. This resource management strategy report focuses on agricultural land stewardship (ALS) strategies that can be incorporated into relevant adaptive management of agricultural land at different levels, including landscape, regional and project.

Agricultural Land Use in California

Public Policy Institute of California (PPIC) | June 25th, 2024

Agricultural Losses from Salinity in California’s Sacramento-San Joaquin Delta

University of California, Davis (UC Davis) | April 5th, 2014

Sea level rise, large-scale flooding, and new conveyance arrangements for water exports may increase future water salinity for local agricultural production in California

Sea level rise, large-scale flooding, and new conveyance arrangements for water exports may increase future water salinity for local agricultural production in California’s Sacramento–San Joaquin Delta. Increasing salinity in crop root zones often decreases crop yields and crop revenues. Salinity effects are nonlinear and vary with crop choice and other factors including drainage and residence time of irrigation water. Here, we explore changes in agricultural production in the Delta under various combinations of water management, large-scale flooding, and future sea level rise. Water management alternatives include through-Delta water exports (current conditions), dual conveyance (through-Delta and a 6,700 Mm3 yr?1 [or 7500 cfs] capacity peripheral canal or tunnel) and the flooding of five western islands with and without peripheral exports. We employ results from previous hydrodynamic simulations of likely changes in salinity for irrigation water at points in the Delta. We connect these irrigation water salinity values into a detailed agro-economic model of Delta agriculture to estimate local crop yield and farm revenue losses. Previous hydrodynamic modeling work shows that sea level rise is likely to increase salinity from 4% to 130% in this century, depending on the increase in sea level and location. Changes in water management under dual conveyance increase salinity mostly in the western Delta, and to a lesser extent in the north, where current salinity levels are now quite low. Because locations likely to experience the largest salinity increases already have a lower-value crop mix, the worst-case losses are less than 1% of total Delta crop revenues. This result also holds for salinity increases from permanent flooding of western islands that serve as a salinity barrier. Our results suggest that salinity increases could have much smaller economic effects on Delta farming than other likely changes in the Delta such as the retirement of agricultural lands after large-scale flooding and habitat development. Integrating hydrodynamic, water salinity, and economic models can provide insights into controversial management issues.

Agricultural managed aquifer recharge (Ag-MAR)—a method for sustainable groundwater management: A review

Critical Reviews in Environmental Science and Technology (Taylor & Francis) | March 28th, 2022

More than two billion people and 40% of global agricultural production depend upon unsustainable groundwater extraction. Managed aquifer recharge (MAR), the practice of s

More than two billion people and 40% of global agricultural production depend upon unsustainable groundwater extraction. Managed aquifer recharge (MAR), the practice of strategically recharging water to replenish subsurface storage, is an important subbasin scale practice for managing groundwater more sustainably. However, it is not yet reaching its full potential to counterbalance growing global groundwater demand. Agricultural managed aquifer recharge (Ag-MAR) is an emerging method for spreading large volume flows on agricultural lands and has capacity for widespread global implementation. Yet, knowledge gaps, synergies, and tradeoffs in Ag-MAR research still exist. We identify six key system considerations when implementing Ag-MAR: water source, soil and unsaturated zone processes, impact on groundwater, crop system suitability, climate change and impact on greenhouse gas emissions, and social and economic feasibility. We describe the present distribution, need for common terminology, and benefits of Ag-MAR including groundwater storage, increased environmental flows, and domestic wells support. We then outline major gaps, namely, water quality impacts, and crop health and yield. We showcase the multidisciplinary approach needed for communication and coordination of Ag-MAR programs with stakeholders and the public and provide a framework for implementation. Finally, we outline a vision for the path to Ag-MAR implementation. Ag-MAR is an important approach for achieving groundwater sustainability. However, it is one of many necessary solutions and does not offset the need for groundwater conservation.