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A Comparative Study for Estimating Crop Evapotranspiration in the Sacramento-San Joaquin Delta

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A Comparative Study for Estimating Crop Evapotranspiration in the Sacramento-San Joaquin Delta
University of California, Davis (UC Davis) | April 23, 2018...
Summary
Consumptive water use by crops, often referred to as evapotranspiration (ET), is frequently the largest component of an agricultural region’s water balance. This study...
Consumptive water use by crops, often referred to as evapotranspiration (ET), is frequently the largest component of an agricultural region’s water balance. This study investigates crop consumptive use in the Sacramento-San Joaquin Delta (“Delta”) of California using a comparative approach with several prominent methods for estimating crop ET, including estimates based on crop coefficients, water balances, energy balance using remote sensing, and field measurements.

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Adaptation Strategies for Agricultural Sustainability in Yolo County, California
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Adaptation Strategies for Agricultural Sustainability in Yolo County, California
California Energy Commission (CEC) | July 31, 2012...
Summary
This place-based case study in an agricultural county in California’s Central Valley focused on the period of 2010–2050, and dealt with biophysical and...
This place-based case study in an agricultural county in California’s Central Valley focused on the period of 2010–2050, and dealt with biophysical and socioeconomic issues related to both mitigation of greenhouse gas (GHG) emissions and to adaptation to an uncertain climate. In the past 100 years, changes in crop acreage has been more related to crop price and availability of irrigation water than to growing degree days during summer, and in fact, summer temperatures have increased less than winter temperatures. Econometric analysis indicated that warmer winters, as projected by Geophysical Fluid Dynamics Laboratory-Bias Corrected Constructed Analog during 2035–2050, could result in less wheat acreage, more alfalfa and tomato acreage, and slight effects on tree and vine crops. The Water Evaluation and Planning (WEAP) model showed that these econometric projections did not reduce irrigation demand under either the B1 or A2 scenarios, but a diverse, water-efficient cropping pattern combined with improved irrigation technology reduced demand to 12 percent below the historic mean.

Collaboration during development of Yolo County’s Climate Action Plan showed that nitrous oxide (mainly from nitrogen fertilizers) was the main source (40 percent) of agricultural emissions. Emissions from cropland and rangeland were several orders of magnitude lower than urbanized land per unit area. A survey distributed to 570 farmers and ranchers achieved a 34 percent response rate. Farmers concerned about climate change were more likely to implement water conservation practices, and adopt voluntary GHG mitigation practices.

Use of the urban growth model (UPlan) showed that channeling much or all future urban development into existing urban areas will increase ecosystem services by preserving agricultural land and open space, immensely reducing the Yolo County’s GHG emissions, and greatly enhancing agricultural sustainability.

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Agricultural Damages and Losses from ARkStorm Scenario Flooding in California

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Agricultural Damages and Losses from ARkStorm Scenario Flooding in California
American Society of Civil Engineers (ASCE) | November 17, 2016...
Summary
Scientists designed the ARkStorm scenario to challenge the preparedness of California communities for widespread flooding with a historical precedence and increased likelihood under...

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.

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Agricultural Irrigation in This Drought: Where is the Water and Where Is It Going?
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Agricultural Irrigation in This Drought: Where is the Water and Where Is It Going?
University of California Giannini Foundation of Agricultural Economics | May 14, 2015...
Summary
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)...
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.

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Agricultural Land Stewardship (Resource Management Strategy)
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Agricultural Land Stewardship (Resource Management Strategy)
California Department of Water Resources (DWR) | July 29, 2016...
Summary
This resource management strategy focuses primarily on private land in agriculture including cultivated land and rangeland. Agricultural land in California comprises about 31.6...
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.

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Agricultural Losses from Salinity in California’s Sacramento-San Joaquin Delta
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Agricultural Losses from Salinity in California’s Sacramento-San Joaquin Delta
San Francisco Estuary & Watershed Science (UC Davis) | April 5, 2014...
Summary
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...
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.

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Agricultural Water Conservation and Efficiency Potential in California
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Agricultural Water Conservation and Efficiency Potential in California
Pacific Institute | June 10, 2014...
Summary
Agriculture uses about 80 percent of California’s developed water supply. As such a large user, it is heavily impacted by the availability and...
Agriculture uses about 80 percent of California’s developed water supply. As such a large user, it is heavily impacted by the availability and reliability of California’s water resources. Agriculture can also play an important role in helping the state achieve a more sustainable water future. The challenge is to transition to an agricultural sector that supplies food and fiber to California and the world and supports rural livelihoods and long-term sustainable water use.

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Agricultural Water Use Efficiency (Resource Management Strategy)
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Agricultural Water Use Efficiency (Resource Management Strategy)
Department of Water Resources | July 29, 2016...
Summary
The agricultural water use efficiency strategy describes the use and application of scientific processes to control agricultural water delivery and use to achieve...
The agricultural water use efficiency strategy describes the use and application of scientific processes to control agricultural water delivery and use to achieve a beneficial outcome. It includes an estimation of net water savings or increased production resulting from implementing efficiency measures as expressed by the ratio of output to input, resulting benefits, and strategies to achieve efficiency and benefits.

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Aluminum- and iron-based coagulation for in-situ removal of dissolved organic carbon, disinfection byproducts, mercury and other constituents from agricultural drain water

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Aluminum- and iron-based coagulation for in-situ removal of dissolved organic carbon, disinfection byproducts, mercury and other constituents from agricultural drain water
Elsevier | May 9, 2019...
Summary
Agricultural production on wetland soils can be significant sources of dissolved organic carbon (DOC), disinfection byproduct precursors, mercury and nutrients to downstream water bodies...
Agricultural production on wetland soils can be significant sources of dissolved organic carbon (DOC), disinfection byproduct precursors, mercury and nutrients to downstream water bodies and accelerate land subsidence. Presented as a potential solution for in-situ water quality improvement and land subsidence mitigation, chemically enhanced treatment wetlands (CETWs) were used to leverage both coagulation and wetland processes. In this study, we evaluated the performance of coagulants ferric sulfate (Fe dosing) and polyaluminum chloride (Al dosing) to remove pollutants from agricultural drain water using the coagulation system designed for CETWs. Both coagulation treatments removed over 70% DOC from source waters, resulting in removal efficiencies (mg-DOC removed per mg-metal dosed) of 1 under Al dosing and 0.5 under Fe dosing. Coagulation by both treatments preferentially removed UV254 active compounds compared to the bulk DOC concentration, suggesting coagulation targeted aromatics more effectively. Phosphates and haloacetic acids were also removed more readily, whereas trihalomethanes, dissolved organic nitrogen and filtered mercury species were removed at similar or lower rates than DOC. Dissolved inorganic nitrogen was not amenable to coagulation and removal was not observed. Freundlich, Langmuir and Monod models explained 33% of the variance in DOC removal for Al dosing and 78–89% of the variance for Fe dosing. All three models indicated Al dosing had higher removal efficiency and affinity for DOC than Fe dosing under study conditions, but when used to predict maximum removal efficiency there was no cohesiveness between the three models due to different model assumptions. Consideration of fluorescence dissolved organic matter and UV254 as surrogates for DOC concentration showed both were equally suitable before coagulant application, but as surrogates after coagulant application, neither could be deemed more fit as a surrogate since both were shown suitable for different treatment scenarios.

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Applying the connectivity approach: Water and food supply projects in California that connect, link, and engage
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Applying the connectivity approach: Water and food supply projects in California that connect, link, and engage
California Roundtable on Water and Food Supply | April 11, 2014...
Summary
In delving into the connectivity concept and approach, members of the California Roundtable on Water and Food Supply (CRWFS) felt that it was...
In delving into the connectivity concept and approach, members of the California Roundtable on Water and Food Supply (CRWFS) felt that it was very important to look to existing and emerging projects that were already embracing the concepts being discussed. Projects were selected to highlight the three high priority areas for effecting change: connected thinking, institutional linkages, and public engagement.

The five examples included in this booklet as case assessments illustrate several ways the connectivity approach is currently being applied throughout California. The assessments are intended to generate ideas for applying the guiding principles of the connectivity approach and the positive impacts that emerge from them. The assessments are not meant to serve as an evaluation of the merit of the projects.

This booklet is intended to accompany From Crisis to Connectivity: Renewed Thinking About Managing California’s Water and Food Supply, which more fully describes the connectivity approach illustrated here.

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A Comparative Study for Estimating Crop Evapotranspiration in the Sacramento-San Joaquin Delta

A Comparative Study for Estimating Crop Evapotranspiration in the Sacramento-San Joaquin Delta

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Adaptation Strategies for Agricultural Sustainability in Yolo County, California

Adaptation Strategies for Agricultural Sustainability in Yolo County, California

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Agricultural Damages and Losses from ARkStorm Scenario Flooding in California

Agricultural Damages and Losses from ARkStorm Scenario Flooding in California

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

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

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Agricultural Land Stewardship (Resource Management Strategy)

Agricultural Land Stewardship (Resource Management Strategy)

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

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

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Agricultural Water Conservation and Efficiency Potential in California

Agricultural Water Conservation and Efficiency Potential in California

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Agricultural Water Use Efficiency (Resource Management Strategy)

Agricultural Water Use Efficiency (Resource Management Strategy)

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Aluminum- and iron-based coagulation for in-situ removal of dissolved organic carbon, disinfection byproducts, mercury and other constituents from agricultural drain water

Aluminum- and iron-based coagulation for in-situ removal of dissolved organic carbon, disinfection byproducts, mercury and other constituents from agricultural drain water

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Applying the connectivity approach: Water and food supply projects in California that connect, link, and engage

Applying the connectivity approach: Water and food supply projects in California that connect, link, and engage

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