Economic Impacts of SGMA on San Joaquin Valley Dairies and Beef Cattle

Dairy Cares (California Cattle Council) | January 30th, 2023

Economic tradeoff between domestic well impact and reduced agricultural production with groundwater drought management: Tulare County, California (USA), case study

Hydrogeology Journal (Springer) | November 8th, 2021

Formal policy analysis can aid resource management where groundwater is used intensively. Approaches for developing equitable and effective pumping allocations for drough

Formal policy analysis can aid resource management where groundwater is used intensively. Approaches for developing equitable and effective pumping allocations for drought are evaluated in the context of the 2012–2016 drought in Tulare County, California, USA. Potential economic impacts of policy alternatives on two user groups with conflicting interests are considered. Tradeoffs between losses of agricultural profit and response costs for domestic wells that run dry are estimated for various maximum groundwater depth policies. A welfare maximizing approach for identifying policies that limit depth to groundwater is evaluated and found to be ineffective because agricultural opportunity costs are much larger than domestic well costs. Adding a fee for additional drought groundwater pumping is proposed as a more impactful and balanced management policy approach. For the case study presented, a fee range of $300 to $600/acre-foot ($300–$600/1,233 m3) yielded an effective groundwater management policy for reducing domestic well impacts from drought and balancing agricultural impacts of drought with the need to replenish additional drought pumping in wetter years. Recent management policies enacted in the study area agree with this finding. These results may provide a useful perspective for analytically examining and developing groundwater management policies near the study area and elsewhere.

Engineer’s Report for the North Fork Kings Groundwater Sustainability Agency: Proposition 218 Procedures for Benefit Assessments

North Fork Kings Groundwater Sustainability Agency (NFKGSA) | January 15th, 2018

The North Fork Kings Groundwater Sustainability Agency (NFKGSA or Agency) recently formed with the primary purpose of compliance with the Sustainable Groundwater

The North Fork Kings Groundwater Sustainability Agency (NFKGSA or Agency) recently formed with the primary purpose of compliance with the Sustainable Groundwater Management Act (SGMA). As a Groundwater Sustainability Agency (GSA), the Agency may develop, adopt, and implement a Groundwater Sustainability Plan (GSP) for sustainable management of groundwater for that portion of the Kings Subbasin (Subbasin) underlying the Agency. The newly formed Agency needs to implement an assessment rate structure that is sufficient to fund Agency operations and required activities pursuant to SGMA. The NFKGSA will develop, in coordination with other GSAs in the Kings Subbasin, a GSP that provides for achieving groundwater sustainability in the Kings Subbasin of the San Joaquin Valley Groundwater Basin underlying the Agency by January 2040. SGMA requires that a GSP be submitted to the California Department of Water Resources (DWR) by January 31, 2020 since the Kings Subbasin is considered a high priority, critically overdrafted subbasin. Based on the Agency’s needs, the NFKGSA Board of Directors is requesting landowner approval to levy assessments to generate sufficient revenue to fund both annual Agency operation costs and expenses associated with the development and implementation of a GSP. The annual operational costs have already begun and are used to fund Agency operations and activities required by SGMA, including retaining consulting firms and legal counsel to provide Agency oversight and lead the Agency through the steps for SGMA compliance. Expenses consist of administrative support, GSP development, and GSP implementation, with GSP development occurring over the next several years and GSA administration and GSP implementation anticipated to be on-going expenses. The administrative annual expenses include an assumed annual 3% inflation factor. The assessments are planned to apply equally to all assessable lands within the Agency’s boundaries. The Assessment Roll provided in Attachment D identifies the acreage for each assessable parcel according to the 2017 tax rolls of Fresno County and Attachment E identifies the acreage for each assessable parcel according to the 2017 tax rolls of Kings County. The following table provides an example schedule of the proposed assessments during the next five years that are the subject of this Proposition 218 Engineer’s Report. The actual assessment rate will be set annually by the Board, based on the budget needs, but will not exceed the proposed maximum rate. Assessments will continue beyond Fiscal Year 2022-23, but at this time the assessment rate after this initial five-year period is unknown because the GSP Implementation costs will not be fully determined until the GSP is developed. The projects that will be proposed as part of the GSP implementation to attain sustainability and maintain the threshold levels established in the GSP will likely require supplemental funding and assessments greater than the maximum assessments recommended in this report, and approval by the landowners in a future Proposition 218 election will be required.

Environmental Baseline Archeological and Historical Resources, Total Water Management Study for the Central Valley Basin, California

U.S. Bureau of Reclamation (USBR) | January 1st, 1975

Environmental Baseline Biological Resources - Fauna, Total Water Management Study for the Central Valley, California

U.S. Bureau of Reclamation (USBR) | January 1st, 1975

Estimates of Natural and Unimpaired Flows for the Central Valley of California: Water Years 1922-2014 (draft)

California Department of Water Resources (DWR) | March 1st, 2016

Estimating regional water supplies that would have occurred absent human activities is a common practice in water resources planning. In this report, such theor

Estimating regional water supplies that would have occurred absent human activities is a common practice in water resources planning. In this report, such theoretical water supply estimates are referred to as “unimpaired” flow. Since 1980, the Department of Water Resources (Department) has periodically published estimates of Central Valley unimpaired flows. In spite of the Department’s previous attempts to distinguish between natural conditions and its calcula tion of theoretical unimpaired flows, unimpaired flow estimates have frequently been used as a surrogate measure of natural conditions, presumably because natural flow estimates were unavailable. A major objective of this report is to clarify the conceptua l differences between natural and unimpaired flows. In this report, the term “unimpaired” flow is used to describe a theoretically available water supply assuming existing river channel conditions in the absence of (1) storage regulation for water supply a nd hydropower purposes and (2) stream diversions for agricultural and municipal uses. Unimpaired flow estimates are theoretical in that such conditions have not occurred historically. In pristine watersheds which have undergone little land use change, unim paired flow estimates provide a fixed frame of reference to develop relationships between precipitation, runoff, and water supply based on long - term hydrologic records. For many years these relationships were based on the assumption of stationarity, i.e. that the past is a good indicator of the future. However, global warming now requires hydrologists and water resources managers to analyze non-stationary processes, requiring more sophisticated tools and techniques to quantify future water supplies. This report updates and extends the Department’s previous published estimates of unimpaired flows for 24 Central Valley sub-basins and the Delta. Monthly unimpaired flows are presented for water years 1922 - 2014.

Estimating the permanent loss of groundwater storage in the southern San Joaquin Valley, California

American Geophysical Union (AGU) | February 23rd, 2017

In the San Joaquin Valley, California, recent droughts starting in 2007 have increased the pumping of groundwater, leading to widespread subsidence. In the southern porti

In the San Joaquin Valley, California, recent droughts starting in 2007 have increased the pumping of groundwater, leading to widespread subsidence. In the southern portion of the San Joaquin Valley, vertical subsidence as high as 85 cm has been observed between June 2007 and December 2010 using Interferometric Synthetic Aperture Radar (InSAR). This study seeks to map regions where inelastic (not recoverable) deformation occurred during the study period, resulting in permanent compaction and loss of groundwater storage. We estimated the amount of permanent compaction by incorporating multiple data sets: the total deformation derived from InSAR, estimated skeletal-specific storage and hydraulic parameters, geologic information, and measured water levels during our study period. We used two approaches, one that we consider to provide an estimate of the lowest possible amount of inelastic deformation, and one that provides a more reasonable estimate. These two approaches resulted in a spatial distribution of values for the percentage of the total deformation that was inelastic, with the former estimating a spatially averaged value of 54%, and the latter a spatially averaged value of 98%. The former corresponds to the permanent loss of m3 of groundwater storage, or roughly 5% of the volume of groundwater used over the study time period; the latter corresponds to the loss of m3 of groundwater storage, or roughly 9% of the volume of groundwater used. This study demonstrates that a data-driven approach can be used effectively to estimate the permanent loss of groundwater storage.

Estimation of groundwater residence time with deeply-derived carbon mixture considered in California

Science of the Total Environment (Elsevier) | December 16th, 2022

Groundwater has experienced long-term overdraft due to drought and human activities in California, resulting in issues of land subsidence and groundwater anthropogenic co

Groundwater has experienced long-term overdraft due to drought and human activities in California, resulting in issues of land subsidence and groundwater anthropogenic contamination. As a useful indicator of groundwater renewal rate and its residence time, groundwater age has been conventionally investigated based on 14C content and 3H concentration. However, the influence of deeply-derived (endogenic) CO2 mixture is not fully and quantitatively considered, although endogenic carbon contributes a large part of the dissolved inorganic carbon in groundwater. Combined with 3H concentration, both conventional and modified 14C-dating methods with endogenic CO2 mixture considered are employed for groundwater age determination in California. On average, the conventional groundwater 14C apparent age is overestimated by ~4.9 kyr or ~26.2 %, causing groundwater recharge rate underestimation and aquifer recovery time overestimation by ~46.0 % and ~26.2 %, respectively. High 3H concentration indicates modern water mixture in more than one fifth of groundwater samples, including those with high modified 14C apparent age (> 12 kyr, i.e., fossil groundwater) in the Central Valley and southern California, which are generally considered not to be recharged by modern water. Modern water mixture in old groundwater can potentially bring anthropogenic contamination to these groundwater resources, which should be paid attentions by the government and the managers. The results have important implications in evaluation of groundwater replenishment and its susceptibility to modern contamination in California, and in groundwater resources estimation globally.

Estuary News, December 2001

San Francisco Estuary Partnership (SFEP) | December 15th, 2001

Estuary News, June 2003

San Francisco Estuary Partnership (SFEP) | June 15th, 2003