Managing Agricultural Irrigation Drainage Water: A guide for developing Integrated On-Farm Drainage Management systems

California State Water Resources Control Board (SWRCB) | May 6th, 2004

Chronic problems of salt, selenium, boron and other naturally occurring elements in surface and groundwater supplies plague agricultural regions throughout the Westside o

Chronic problems of salt, selenium, boron and other naturally occurring elements in surface and groundwater supplies plague agricultural regions throughout the Westside of the San Joaquin Valley and the western U.S. Compounding the problem is the build-up of salty subsurface groundwater resulting from dense clay layers and inadequate natural drainage. The Integrated On-Farm Drainage Management (IFDM) system was developed to manage these problems. A state-of-the-art, yet practical irrigation management system, the IFDM provides for drainage water reuse to improve water availability for crop production and to minimize salt and selenium risks to water quality and the environment. IFDM manages irrigation water on salt sensitive, high value crops and reuses drainage water to irrigate salt-tolerant crops, trees and halophyte plants. Salt and selenium are removed from the farming system and can be marketed. This system views the subsurface drainage water containing salts and selenium as resources, rather than considering them as wastes and environmental problems.

McMullin Area Groundwater Sustainability Agency Groundwater Sustainability Plan

McMullin Area Groundwater Sustainability Agency (MAGSA) | November 6th, 2019

McMullin Area Groundwater Sustainability Agency Groundwater Sustainability Plan (Revised)

McMullin Area Groundwater Sustainability Agency (MAGSA) | July 6th, 2022

Merced Groundwater Subbasin Groundwater Sustainability Plan

Merced Subbasin Groundwater Sustainability Agency (MSGSA) | November 12th, 2019

Merced River Watershed Flood-MAR Reconnaissance Study

California Department of Water Resources (DWR) | November 15th, 2023

DWR, in partnership with the Merced Irrigation District (MID), is conducting a preliminary study using flood waters for managed aquifer recharge that can reduce flood ris

DWR, in partnership with the Merced Irrigation District (MID), is conducting a preliminary study using flood waters for managed aquifer recharge that can reduce flood risk, increase surface and groundwater supply reliability, and enhance ecosystems in the Merced River Basin. This Merced River Reconnaissance Study (study) is exploring the potential, feasibility, and effectiveness of Flood-MAR concepts, testing theories, and assessing strategies in overcoming barriers and challenges to project planning and implementation. The study will assess current conditions of the Merced River watershed and the vulnerability of these watershed management characteristics to a range of potential climate change futures. The study will also describe the public and private benefits that may be achieved through Flood-MAR strategies and quantify a range of benefits that Flood-MAR could provide in or adjacent to the Merced River watershed.

Meteorological driving forces of reference evapotranspiration and their trends in California

Science of the Total Environment (Elsevier) | August 13th, 2022

Reference evapotranspiration (ETo) is a variable that helps determine atmospheric pressure on living (reference) grass to release water into the atmosphere. For this purp

Reference evapotranspiration (ETo) is a variable that helps determine atmospheric pressure on living (reference) grass to release water into the atmosphere. For this purpose, four main driving forces: air temperature, air humidity, solar radiation, and wind speed need to be measured over the well-watered reference grass. The relative influence of these driving forces is region and climate-specific, with daily and seasonal variations. A clear understanding of the dynamic interactions of ETo's driving factors can illuminate the water and energy cycles of the earth and assist modelers with more accurate predictions of ETo. In this study, Pearson correlation, mutual information, and random forest feature importance analyses have been used to evaluate the relative importance of meteorological driving forces of ETo in California. To better understand the interrelations of these variables, 1,365,823 daily data samples from 237 standardized weather stations for 36 years have been clustered into homogeneous climatic zones and analyzed. To compensate for the effects of seasonality, feature importance analysis is also conducted on seasonal and monthly clustered data. Moreover, seasonal and annual trends of ETo and its driving factors are investigated for California and homogeneous zones using the Mann-Kendall test. Our findings reveal that for annually clustered data, solar radiation is the most influential driving factor of ETo in California. However, analysis of seasonal and monthly clustered data shows that vapor pressure deficit is the most informative factor during the summer and spring, while solar radiation is more important during the colder seasons. Results of trend analysis don't suggest a consistent monotonic trend for ETo and other variables for different seasons and zones. However, it is shown that agricultural regions with heavy irrigation dependence like the Central Valley are getting warmer and drier, especially during the irrigation season. This can adversely affect the water resources, agriculture industry, and food production of California, and modeling efforts like this can be very informative for future water resources management.

Methods of Analysis—Determination of Pesticides in Filtered Water and Suspended Sediment using Liquid Chromatography- and Gas Chromatography-Tandem Mass Spectrometry

U.S. Geological Survey (USGS) | January 31st, 2024

The widespread application of pesticides in agricultural and urban areas leads to their presence in surface waters. Presence of these biologically active chemicals in en

The widespread application of pesticides in agricultural and urban areas leads to their presence in surface waters. Presence of these biologically active chemicals in environmental waters potentially has adverse effects on nontarget organisms. To better understand the environmental fate of these contaminants, a robust method to capture chemicals with wide-ranging physicochemical properties has been developed. The method was developed by the U.S. Geological Survey’s Organic Chemistry Research Laboratory to monitor pesticides, pesticide degradates, and other agrochemicals in environmental surface waters throughout the country. The analysis involves a multiresidue method to determine 183 pesticides and pesticide degradates in filtered water samples and 178 pesticides and pesticide degradates in paired suspended sediment samples. After the filtration of whole water, contaminants are individually measured in the filtered water and the collected suspended sediment. Filtered water is extracted via solid-phase extraction, whereas suspended sediment is extracted using an ultrasonication, solid-liquid extraction. Samples are analyzed by liquid chromatography-tandem mass spectrometry using an electrospray ionization source in positive and negative modes and analyzed by gas chromatography-tandem mass spectrometry using an advanced electron ionization source in positive mode. Instrument parameters were optimized for the highest sensitivity, and at least two transitions (quantifier and qualifier) were monitored for each analyte. Recoveries in test filtered water (n=9; 183 analytes) from the American River, California, and suspended sediment (n=9; 178 analytes) samples fortified at 15 nanograms per liter (ng/L) ranged from 70.1 to 121.0 and 71.1 to 117.0 percent in water and suspended sediment filter samples, respectively.

Mid-Kaweah Groundwater Sustainability Agency Groundwater Sustainability Plan

Mid-Kaweah Groundwater Sustainability Agency (MKGSA) | December 18th, 2019

Minimizing the Impact of Cannabis Cultivation on California Lands and Waterways

California State Water Resources Control Board (SWRCB) | February 17th, 2017

Following recent changes in state law and voter-approved initiatives, California’s commercial cultivation of cannabis for recreational and medical use is expected to gr

Following recent changes in state law and voter-approved initiatives, California’s commercial cultivation of cannabis for recreational and medical use is expected to grow significantly. The State Water Resources Control Board has adopted a state cannabis policy to set up strict environmental standards, and a permitting system to protect local surface water from dewatering, protect water habitat and prevent pollution in the state’s rivers and streams. Left unregulated, cannabis cultivation can pose serious threats to water quality and the environment. Cannabis cultivation impacts include the release of fertilizers, pesticides and other supplements that degrade water quality and threaten wildlife. Excessive water diversions can injure fish or even dewater smaller streams. The physical alteration of the land can harm stream habitat and wildlife by the sediment and debris that is deposited in waterways by unregulated cultivation. Overview: The State Water Board’s “Cannabis Cultivation Policy, Principles and Guidelines for Cannabis Cultivation” (Policy) will be implemented through a water quality permit and a water right. The water quality permit is referred to as a Statewide General Order for Cannabis Cultivation Activities (Cannabis General Order). The water right is referred to as a Cannabis Small Irrigation Use Registration. Tiered Approach: The Cannabis General Order consists of a tiered permit structure based on threat to water quality. Tier 1 Cannabis Cultivators have a disturbed area greater than 2,000 square feet and less than 1 acre (43,560 square feet). Tier 2 Cannabis Cultivators have a disturbed area equal to or greater than 1 acre.

Modeling guides groundwater management in a basin with river–aquifer interactions

California Agriculture (UCANR) | March 13th, 2018

The Sustainable Groundwater Management Act (SGMA) of 2014 seeks to maintain groundwater discharge to streams to support environmental goals. In Scott Valley, in Siskiyou

The Sustainable Groundwater Management Act (SGMA) of 2014 seeks to maintain groundwater discharge to streams to support environmental goals. In Scott Valley, in Siskiyou County, the Scott River and its tributaries are an important salmonid spawning habitat, and about 10% of average annual Scott River stream flow comes from groundwater. The local groundwater advisory committee is developing groundwater management alternatives that would increase summer and early fall stream flows. We developed a model to provide a framework to evaluate those alternatives. We first created a water budget for the Scott Valley groundwater basin and integrated the detailed, spatiotemporally distributed water budget results into a computer model of the basin that simultaneously accounted for groundwater flow, stream flow and landscape water fluxes. Different conceptual representations (using the MODFLOW RIV package and MODFLOW SFR package) of the stream–aquifer boundary provided significantly different results in the seasonal dynamics of groundwater–surface water fluxes. As groundwater sustainability agencies draw up plans to meet SGMA requirements, they must choose and test simulation tools carefully.