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2016 Annual Report of Hydrogeologic Conditions, Water Requirements, Supplies and Disposition Santa Maria Valley Management Area

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2016 Annual Report of Hydrogeologic Conditions, Water Requirements, Supplies and Disposition Santa Maria Valley Management Area
City of Santa Maria | April 13, 2017...
Summary
This annual report of conditions in the Santa Maria Valley Management Area, for calendar year 2016, has been prepared to meet the reporting conditions...
This annual report of conditions in the Santa Maria Valley Management Area, for calendar year 2016, has been prepared to meet the reporting conditions of the June 30, 2005, Stipulation entered by the Superior Court of the State of California, County of Santa Clara, in the Santa Maria Valley Groundwater Basin litigation. The Stipulation divided the overall Santa Maria Valley Groundwater Basin into three management areas, the largest of which overlies the main Santa Maria Valley (the Santa Maria Valley Management Area, or SMVMA) and is the subject of this report. The other two management areas, the Nipomo Mesa Management Area (NMMA) and the Northern Cities Management Area, are addressed in separate annual reports prepared by others.

The Stipulation, approved and implemented in 2008, specifies that monitoring shall be sufficient to determine groundwater conditions, land and water uses, sources of water supply, and the disposition of all water supplies in the Basin. Annual Reports for the SMVMA are to summarize the results of the monitoring and include an analysis of the relationship between projected water demand and supply. The Stipulation was preserved in the California Court of Appeal (Sixth Appellate District) Decision of November 21, 2012, and in the Superior Court of the State of California (County of Santa Clara) Final Judgment of April 23, 2014. Thus, the Physical Solution criteria for monitoring and managing groundwater in the basin remain.

In accordance with the Stipulation, this report on the SMVMA provides a description of the physical setting and briefly describes previous studies conducted in the groundwater basin, including the long-term monitoring program developed for the SMVMA. As reported herein, the Twitchell Management Authority (TMA) commissioned the preparation of a monitoring program for the SMVMA in 2008, and its complete implementation is expected to provide the data with which to fully assess future conditions. This report describes hydrogeologic conditions in the management area historically and through 2016, including groundwater conditions, Twitchell Reservoir operations, and hydrologic and climatic conditions. As with all previous annual reports (commencing in 2008), the water requirements and supplies for agricultural and municipal uses are accounted, as are the components of water disposition in the SMVMA.

Conclusions drawn regarding water resource conditions are discussed, including any finding of severe water shortage, which is concluded to not be the case through 2016. Finally, recommendations are provided with regard to the intra-basin transfer of water from the SMVMA to the NMMA, possible enhancement of groundwater recharge, expanded assessment of water resource conditions, and continued implementation of the monitoring program for the SMVMA.

Janny Choi from Stanford University's Water in the West discusses the Santa Maria stipulation in the 2014 paper Before the Well Runs Dry: Improving the Linkage Between Groundwater and Land Use Planning.

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A New Approach to Accounting for Environmental Water Insights from the Sacramento–San Joaquin Delta
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A New Approach to Accounting for Environmental Water Insights from the Sacramento–San Joaquin Delta
Public Policy Institute of California (PPIC) | November 9, 2017...
Summary
How water is apportioned to California’s cities, farms, and the environment can lead to conflict and competition in times of drought. Allocation of...
How water is apportioned to California’s cities, farms, and the environment can lead to conflict and competition in times of drought. Allocation of water to the environment in particular is poorly accounted for and poorly understood—shortcomings that can affect water policy, decision making, and public perception. This report reviews the state’s long-standing methods for defining and accounting for environmental water and proposes reforms to improve the timeliness, transparency, and detail in the accounting of environmental water allocation.

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Accounting for California’s Water
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Accounting for California’s Water
Public Policy Institute of California (PPIC) | July 13, 2016...
Summary
Understanding California’s water balance sheet—how much there is, who has claims to it, and what is actually being “spent”—is key to effectively managing...
Understanding California’s water balance sheet—how much there is, who has claims to it, and what is actually being “spent”—is key to effectively managing the state’s limited water supply in support of a healthy economy and environment. The latest drought has spotlighted serious gaps and fragmentation in California’s water accounting system.

In this report, we identify gaps in California’s water information systems. We recommend that the state adopt an overarching goal of modernizing its water accounting, and that key state agencies—supported by an oversight committee of key stakeholders and independent experts—develop and adopt a common accounting framework. We outline a dozen priority actions to strengthen water accounting by: improving measurements and estimates of water availability and use; firming up legal claims on water rights and water reserved for the environment; establishing protocols, standards, and models for transparent water accounting at all levels across the state; and making water information more available and accessible to water managers, water users, policymakers, and the public.

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Annual Ground-Water Discharge by Evapotranspiration from Areas of Spring-Fed Riparian Vegetation Along the Eastern Margin of Death Valley, 2000–02

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Annual Ground-Water Discharge by Evapotranspiration from Areas of Spring-Fed Riparian Vegetation Along the Eastern Margin of Death Valley, 2000–02
U.S. Geological Survey (USGS) | July 1, 2006...
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Considering Water Use Efficiency for the Environmental Sector
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Considering Water Use Efficiency for the Environmental Sector
California Department of Water Resources (DWR) | April 29, 2010...
Summary
The goal of this report is to provide a starting point from which the water planning community can move toward improving the allocation...
The goal of this report is to provide a starting point from which the water planning community can move toward improving the allocation of water within the environmental sector. To facilitate that process, this report presents:

1. A discussion that highlights the water community’s points of agreement on the concept of analyzing the application of water to the environment
2. A term, Managed Environmental Water Use Efficiency (MEWUE), to reflect that concept, and a definition of that term
3. A survey of existing methods that could be used to develop MEWUE
4. Suggestions about how to proceed with implementing MEWUE

Based on our analysis, we found that there was genuine interest in understanding and improving how water is allocated to the environment. The idea of maximizing environmental benefits for a given amount of allocated water is a unifying thread among stakeholder interests. We focus on this idea throughout the report as the central concept that MEWUE is intended to achieve.

We propose a new term to reflect the stated concerns of stakeholders that other terms, Environmental Water Use Efficiency and Ecosystem Restoration Water Use Efficiency, did not fully address. We propose Managed to indicate that MEWUE does not evaluate the environment’s use of water per se but rather the effectiveness of water in controlled systems.

We propose Environmental to reflect the range of “uses” of water in the ecosystem, including ecosystem maintenance, restoration, and water quality. Lastly, we support the use of the word Efficiency because efficiency communicates the intent of maximizing benefit for a given amount of water, providing a basis for comparison of the benefits obtainable from different uses of that water.

MEWUE: a mechanism to analyze alternative uses of managed environmental water to determine which allocation of a given amount of water will maximize environmental benefits, and a means to improve decision-making over time.

We address the issue of why having an explicit decision-making mechanism is essential. It is hard to allay the fears that some have of incorrectly measuring environmental benefits. However, it is even more difficult to claim that decisions based on implicit measures and beliefs are better for the environment than those based on some imperfect but explicit consideration of environmental benefits.

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Depletion and Capture: Revisiting “The Source of Water Derived from Wells”

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Depletion and Capture: Revisiting “The Source of Water Derived from Wells”
National Ground Water Association (NGWA) | May 28, 2014...
Summary
A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion...
A natural consequence of groundwater withdrawals is the removal of water from subsurface storage, but the overall rates and magnitude of groundwater depletion and capture relative to groundwater withdrawals (extraction or pumpage) have not previously been well characterized. This study assesses the partitioning of long‐term cumulative withdrawal volumes into fractions derived from storage depletion and capture, where capture includes both increases in recharge and decreases in discharge. Numerical simulation of a hypothetical groundwater basin is used to further illustrate some of Theis' (1940) principles, particularly when capture is constrained by insufficient available water. Most prior studies of depletion and capture have assumed that capture is unconstrained through boundary conditions that yield linear responses. Examination of real systems indicates that capture and depletion fractions are highly variable in time and space. For a large sample of long‐developed groundwater systems, the depletion fraction averages about 0.15 and the capture fraction averages about 0.85 based on cumulative volumes. Higher depletion fractions tend to occur in more arid regions, but the variation is high and the correlation coefficient between average annual precipitation and depletion fraction for individual systems is only 0.40. Because 85% of long‐term pumpage is derived from capture in these real systems, capture must be recognized as a critical factor in assessing water budgets, groundwater storage depletion, and sustainability of groundwater development. Most capture translates into streamflow depletion, so it can detrimentally impact ecosystems.

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Evaluating Micrometeorological Estimates of Groundwater Discharge from Great Basin Desert Playas

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Evaluating Micrometeorological Estimates of Groundwater Discharge from Great Basin Desert Playas
National Ground Water Association (NGWA) | March 6, 2018...
Summary
Groundwater availability studies in the arid southwestern United States traditionally have assumed that groundwater discharge by evapotranspiration (ETg) from desert playas is a...
Groundwater availability studies in the arid southwestern United States traditionally have assumed that groundwater discharge by evapotranspiration (ET_g) from desert playas is a significant component of the groundwater budget. However, desert playa ET_g rates are poorly constrained by Bowen ratio energy budget (BREB) and eddy‐covariance (EC) micrometeorological measurement approaches. Best attempts by previous studies to constrain ET_g from desert playas have resulted in ET_g rates that are within the measurement error of micrometeorological approaches. This study uses numerical models to further constrain desert playa ET_g rates that are within the measurement error of BREB and EC approaches, and to evaluate the effect of hydraulic properties and salinity‐based groundwater density contrasts on desert playa ET_g rates. Numerical models simulated ET_g rates from desert playas in Death Valley, California and Dixie Valley, Nevada. Results indicate that actual ET_g rates from desert playas are significantly below the uncertainty thresholds of BREB‐ and EC‐based micrometeorological measurements. Discharge from desert playas likely contributes less than 2% of total groundwater discharge from Dixie and Death Valleys, which suggests discharge from desert playas also is negligible in other basins. Simulation results also show that ET_g from desert playas primarily is limited by differences in hydraulic properties between alluvial fan and playa sediments and, to a lesser extent, by salinity‐based groundwater density contrasts.

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Geohydrology and Simulated Response to Ground-Water Pumpage in Carson Valley, A River-Dominated Basin in Douglas County, Nevada, and Alpine County, California
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Geohydrology and Simulated Response to Ground-Water Pumpage in Carson Valley, A River-Dominated Basin in Douglas County, Nevada, and Alpine County, California
U.S. Geological Survey (USGS) | May 2, 1986...
Summary
This investigation of the ground-water hydrology in Carson Valley was conducted from 1980 through 1985 by the U.S. Geological Survey, in cooperation with...
This investigation of the ground-water hydrology in Carson Valley was conducted from 1980 through 1985 by the U.S. Geological Survey, in cooperation with Douglas County. The purpose of the study was to:

(1) collect, compile, and analyze hydrologic data to quantify the hydrology of the valley and to enhance the understanding of the valley's geohydrologic system; and

(2) develop a ground-water model that would simulate the response of the hydrologic system to applied stresses and that could be used to estimate the probable hydrologic effects of various development alternatives.

This report presents the results of the investigation.

Work began with a gravity survey in 1980 to determine the depth to bedrock in Carson Valley; the results are discussed in detail in a separate publication (Maurer, 1986). From 1981 to 1983, work included:

(1) measurement of water-level fluctuations and surface-water runoff,

(2) drilling of additional observation wells,

(3) collection of ground-water pumpage data and measurement of pump efficiencies, and

(4) compilation of existing data reports and drillers 1 logs to obtain estimates of geohydrologic characteristics of the ground-water reservoir.

Development of a water budget and initial estimates of hydraulic conductivities and specific yield were accomplished in 1983. From 1983 to 1985, the ground-water model was developed and calibrated, and simulations of possible ground-water development were made. The model, which represents a compilation of all available data, was used to

(1) test estimates of the geohydrologic characteristics of the ground-water reservoir,

(2) evaluate the components of the water budget for the basin,

(3) enhance the understanding of the hydrologic flow system in the basin, and

(4) simulate the effect of various possible developmental alternatives on Carson River outflow, evapotranspiration, ground-water levels, and ground-water storage in the valley.

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Groundwater Availability of the Central Valley Aquifer
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Groundwater Availability of the Central Valley Aquifer
U.S. Geological Survey (USGS) | July 15, 2009...
Summary
California’s Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250...
California’s Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the Central Valley with an estimated value of $17 billion per year. This irrigated agriculture relies heavily on surface-water diversions and groundwater pumpage. Approximately one-sixth of the Nation’s irrigated land is in the Central Valley, and about one-fifth of the Nation’s groundwater demand is supplied from its aquifers.

The Central Valley also is rapidly becoming an important area for California’s expanding urban population. Since 1980, the population of the Central Valley has nearly doubled from 2 million to 3.8 million people. The Census Bureau projects that the Central Valley’s population will increase to 6 million people by 2020. This surge in population has increased the competition for water resources within the Central Valley and statewide, which likely will be exacerbated by anticipated reductions in deliveries of Colorado River water to southern California. In response to this competition for water, a number of water-related issues have gained prominence: conservation of agricultural land, conjunctive use, artificial recharge, hydrologic implications of land-use change, and effects of climate variability.

To provide information to stakeholders addressing these issues, the USGS Groundwater Resources Program made a detailed assessment of groundwater availability of the Central Valley aquifer system, that includes: (1) the present status of groundwater resources; (2) how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change.

This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at differing scales. The principal product of this new assessment is a tool referred to as the Central Valley Hydrologic Model (CVHM) that accounts for integrated, variable water supply and demand, and simulates surface-water and groundwater-flow across the entire Central Valley system.

The development of the CVHM comprised four major elements: (1) a comprehensive Geographic Information System (GIS) to compile, analyze and visualize data; (2) a texture model to characterize the aquifer system;(3) estimates of water-budget components by numerically modeling the hydrologic system with the Farm Process (FMP); and (4) simulations to assess and quantify hydrologic conditions.

Chapter A: Introduction, Overview of Hydrogeology, and Textural Model of
California’s Central Valley

Chapter B: Groundwater Availability in California’s Central Valley

Chapter C: Numerical Model of the Hydrologic Landscape and Groundwater Flow in California’s Central Valley

Appendix 1: Supplemental Information—Modifications to
Modflow-2000 Packages and Processes

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Groundwater: The Water-Budget Myth

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Groundwater: The Water-Budget Myth
National Academy of Sciences | June 1, 1982...
Summary
Water-resource scientists are concerned that some basic principles are being overlooked by water managers. Rather than discuss the scope of groundwater hydrology, we...

Water-resource scientists are concerned that some basic principles are being overlooked by water managers. Rather than discuss the scope of groundwater hydrology, we have chosen to focus on a common misconception to illustrate the point. Perhaps the most common misconception in groundwater hydrology is that a water budget of an area determines the magnitude of possible groundwater development. Several well-known hydrologists have addressed this misconception and attempted to dispel it. Somehow, though, it persists and continues to color decisions by the water-management community. The laws governing the development of groundwater in Nevada as well as several other states are based on the idea that pumping within a groundwater basin shall not exceed the recharge. It is the intent of this paper to re-examine the issue.

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2016 Annual Report of Hydrogeologic Conditions, Water Requirements, Supplies and Disposition Santa Maria Valley Management Area

2016 Annual Report of Hydrogeologic Conditions, Water Requirements, Supplies and Disposition Santa Maria Valley Management Area

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A New Approach to Accounting for Environmental Water Insights from the Sacramento–San Joaquin Delta

A New Approach to Accounting for Environmental Water Insights from the Sacramento–San Joaquin Delta

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Accounting for California’s Water

Accounting for California’s Water

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Annual Ground-Water Discharge by Evapotranspiration from Areas of Spring-Fed Riparian Vegetation Along the Eastern Margin of Death Valley, 2000–02

Annual Ground-Water Discharge by Evapotranspiration from Areas of Spring-Fed Riparian Vegetation Along the Eastern Margin of Death Valley, 2000–02

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Considering Water Use Efficiency for the Environmental Sector

Considering Water Use Efficiency for the Environmental Sector

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Depletion and Capture: Revisiting “The Source of Water Derived from Wells”

Depletion and Capture: Revisiting “The Source of Water Derived from Wells”

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Evaluating Micrometeorological Estimates of Groundwater Discharge from Great Basin Desert Playas

Evaluating Micrometeorological Estimates of Groundwater Discharge from Great Basin Desert Playas

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Geohydrology and Simulated Response to Ground-Water Pumpage in Carson Valley, A River-Dominated Basin in Douglas County, Nevada, and Alpine County, California

Geohydrology and Simulated Response to Ground-Water Pumpage in Carson Valley, A River-Dominated Basin in Douglas County, Nevada, and Alpine County, California

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Groundwater Availability of the Central Valley Aquifer

Groundwater Availability of the Central Valley Aquifer

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Groundwater: The Water-Budget Myth

Groundwater: The Water-Budget Myth

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