Physical Sciences and Mathematics Commons^™

2003 - Geohydrologic Framework Of Recharge And Seawater Intrusion In The Pajaro Valley, Santa Cruz And Monterey Counties, California

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

The Pajaro Valley Water Management Agency (PVWMA) must deal with issues of both water supply and water quality. Managing water resources for agricultural and municipal users requires maintaining a reliable water supply to meet growing demands while preventing ground-water overdraft and the related degradation of water quality. Important regional water-quality concerns include increased nitrate concentrations and seawater intrusion. To protect the quantity and quality of the ground-water supplies, the PVWMA has implemented a plan to prevent further seawater intrusion. In order to evaluate how these activities can be conducted most effectively, it is necessary to improve the understanding of the …

2014 - State Of The Salinas River Groundwater Basin Report, Executive Summary

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

An examination of the state of the Salinas River Groundwater Basin (Basin) was conducted in the last half of 2014 as part of the larger Basin Investigation. This Executive Summary of the State of the Basin Report addresses the ramifications of prolonged drought by considering likely changes in groundwater head elevations, groundwater storage, and seawater intrusion in the event that the current drought continues. In addition, some steps are presented that could be taken to help alleviate the consequences of further depleting groundwater storage.

2015 - Basin Study Workshop - State Of The Salinas River Groundwater Basin Report

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

The Salinas River Groundwater Basin report provided a snapshot of the current conditions within Zone 2C. The report also addressed the ramifications of prolonged drought by considering potential changes in:

• groundwater storage,
• groundwater head elevations, and
• seawater intrusion

The report provided technical options that could help alleviate the consequences of continued drought conditions

2007 - El Toro Groundwater Study Monterey County, California

Monterey County Water Resources Agency Engineering Reports

The primary objective of this study was to evaluate groundwater resource capacity of the El Toro Planning Area and recommend maintaining or revising the B-8 zoning overlay. Additional objectives and tasks completed for this study were consistent with recommendations of the1996 Fugro report and included compiling water well and hydrostratigraphic information for the El Toro Planning Area; conducting aquifer testing; collecting and analyzing water samples from wells; developing a conceptual hydrogeologic model of the El Toro Planning Area; and evaluating hydrogeologic connectivity between existing subareas.

2001 - Hydrogeologic Investigation Of Salinas Valley Basin In The Vicinity Of Fort Ord And Marina Salinas Valley, California - Final Report

Monterey County Water Resources Agency Engineering Reports

This report evaluated the then current state or potential for seawater intrusion in the city of Marina and the former Fort Order area. Groundwater from this area primarily supplied drinking water wells as opposed to agricultural wells. Aquifers evaluated in this study area include the perched zone or A-aquifer, the Pressure 180-Foot Aquifer (180-Foot Aquifer), the Pressure 400-Foot Aquifer ( 400-Foot Aquifer), the Deep Aquifer, and aquifers within the Purisima and Santa Margarita Formations. The I80-Foot and 400-Foot Aquifers are the focus of this study because both aquifers outcrop along the canyon walls of Monterey Bay where they interface with …

2002 - North Monterey County Comprehensive Water Resources Management Plan

Monterey County Water Resources Agency Water Reports

North Monterey County experiences severe water supply and quality problems including falling water levels, seawater intrusion, and nitrate contamination. The region is in a significant state of overdraft where current demands greatly exceed the annual level of recharge. Without increased supplies, dramatic changes need to occur to the North County land use pattern to reduce demand. The Comprehensive Water Resources Management Plan combines water conservation, water supply, water quality, and land use actions into comprehensive policy alternatives. It is clear, however, that capital facilities are necessary if the problem is to be solved.

The study area overlies a portion of …

2003 - Geohydrologic Framework Of Recharge And Seawater Intrusion In The Pajaro Valley, Santa Cruz And Monterey Counties, California

Monterey County Water Resources Agency Engineering Reports

This report provided the Salinas groundwater basin hydrogeology informaion documented since the 1950s in order to provide a better understanding of the advancement of seawater intrusion into groundwater zones. Since the later 1990s, well logs, geopyhsical and lithological data supporting a three-dimensional study of the inter-related ancestral fluvial and alluvial-fan depositional environments making up the groundwater bearing zones (180-Foot and 400-Foot aquifers) and their implications on seawater intrusion pathways.

The economic importance of a detailed rendition of hydrostratigraphic characteristics was to assist in the construction and placement of future water supply and monitoring wells within the study area. Seawater was …

1998 - Salinas Valley Water (Preliminary Analysis Of) The Cause And Cost Of Seawater Intrusion

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

An analysis of the historical cause of seawater intrusion in the Pressure Area of Monterey County. An annual overdraft of groundwater resources near the coast coupled with a seasonal cycle of over pumping created a reversal in the groundwater gradient and associated cones of depression. "Marine intrusion has occurred in the 180-foot aquifer in recent years as a result of overdrafts." (Bulletin 52, 1946, p.27). The only overdrafts on groundwater in the Salinas Valley were in the East Side and Pressure Areas. "There was no shortage of groundwater in the remainder of the basin and no threat of deficiency under …

2014 - Quarternary Geologic Map Of North-Central Salinas River Valley And Arroyo Seco

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

The new mapping provides a detailed stratigraphic history of incision and deposition from the early Pleistocene to the present. Infiltration from the Salinas River and its tributaries is the source of irrigation water in this agricultural region. Irrigation water is pumped from the aquifers at depths of about 55 and 120 m. Area has become intruded by seawater, especially between cities of Castroville and Salinas.

2015 - Salinas River Watershed Area Salt Modeling Assessment Prepared For California Central Coast Regional Water Quality Control Board And The U.S. Environmental Protection Agency, Region Ix

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

A November 2015 report prepared by Tetra Tech for California Central Coast Regional Water Quality Control Board and the U.S. Environmental Protection Agency, Region IX. The purpose was for the informed development of salt-related TMDLs by the CCRWQCB and a salt and nutrient management plan for the Salinas Valley aquifers. Three reaches reported 2010 303(d) listings for salt-related impairments in these watersheds including impairments due to chloride, sodium, electrical conductivity, and total dissolved solids – Lower Salinas River, Santa Rita Creek, and Alisal Creek. This report provides data analysis and a literature review (Sections 1 through 5), development of a …

2017, October - Recommendations To Address The Expansion Of Seawater Intrusion In The Salinas Valley Groundwater Basin

Monterey County Water Resources Agency Engineering Reports

This report provides a discussion of the current knowledge and related background information surrounding seawater intrusion pathways and potential impacts thereof on the Salinas Valley Groundwater Basin. The report also serves as a body of evidence to catalogue the findings used to support the six recommendations presented. Each recommendation can be implemented on its own or in concert with the others, and the relative importance of each is discussed individually in this report. However, the recommendations are conceptualized as a comprehensive solution that, along with continued operation of projects that have been constructed for the same purpose, have the strongest …

2015 – Project Justification – Addressing An Urgent Water Supply Need For A Disadvantaged Community In The Greater Monterey County Irwm Region

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

One hundred percent of Castroville’s water supply comes from the 400-foot aquifer of the Pressure sub-basin of the Salinas Valley Groundwater Basin. Groundwater levels in the aquifer dropped more than 100 feet below the seal level as of July 2015 at static conditions. Water levels dropped to more than 190 feet below the mean sea level during operation of the water well. The dramatic drop combined with the close proximity of the Pacific Ocean (less than 4 miles) and to existing seawater intrusion (less than ¼ mile) raised significant alarm that the existing water supply system to Castroville was imminently …

2013, November 19 - Protective Elevations To Control Sea Water Intrusion In The Salinas Valley, Geoscience For Mcwra

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

A report prepared in support of preventing revocation of Permit 1043 (State of California Division of Water Rights Permit for Diversion of Use of Water – Amended Permit 11043 dated 110-Jul-49) that allows for appropriation of water from the Salinas River in Monterey County California not to exceed 400 cfs with annual maximum diversion not to exceed 168,538 acre feet per year. The report addresses the potential beneficial uses of diverting water to help increase groundwater levels in the Pressure and East Side Subareas that would in turn help to control seawater intrusion.

2015, November - Salinas River Salt Modeling Report , Tetra Tech For California Central Coast Regional Water Quality Control Board And Us Environmental Protection Agency, Region Ix

State and Federal Documents Relating to Monterey and San Luis Obispo Counties

Report prepared by Tetra Tech on behalf of California Central Coast Regional Water Quality Control Board and US Environmental Protection Agency, Region IX with a view of development of salt-related TMDLs and a salt and nutrient management plan for the Salinas Valley aquifers. The report provides data analysis and a literature review, development of a water and salt mass balance tool, and salt sources assessment. Recommendations regarding improved representation of cropland locations, rotations, and irrigation practices are provided.

1999 - Salinas River Watershed Management Action Plan, Central Coast Regional Water Quality Control Board

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

To more effectively protect and improve water resources, the Action Plan attempts to develop local solutions to local problems. Many significant identified water quality impacts in the Salinas River Watershed, such as erosion and sedimentation, nitrates in the groundwater and surface water, and older, discontinued pesticides in sediments and animal tissues, are primarily associated with nonpoint pollution sources. Also, widespread groundwater pumping contributes significantly to seawater intrusion into the coastal aquifers. The Action Plan approach includes: 1. devoting additional Regional Board resources to watershed activities, 2. increasing the Regional Board presence by developing partnerships with landowners, local governments, resource agencies …

1999 - Water Resources And Land Use Change In Salinas Valley, Watershed Institute Report No. Wi-1999-01

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

The 1999 report prepared by Fred Watson, Lars Pierce, Mel Mulitsch, Wendi Newman, Adrian Rocha, Mark Fain and Jodiah Nelson of the Watershed Institute, describes the progress made toward the use of computer modeling to provide both understanding and predictive capability. The Salinas River watershed of over 11,000 square kilometers supports large areas of intensive agriculture production, including large areas of intensive crop production, and extensive cattle ranches supporting annual grasslands. Mainly a dry climate with limited surface water resources, the valley has a finite groundwater system. Agriculture accounts for 93.5% of the groundwater extractions that exceed recharge by 40,000-50,000 …

2015, Aug. 20 - Groundwater Recharge On East Side Soils Of The Salinas Valley

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

Discussion of the historically low groundwater levels in the Salinas Valley, noting that the shallower wells have become unreliable. As the groundwater levels drop below sea level, the seawater intrusion in the coastal aquifers will worsen. Because of the fast-declining groundwater levels on the east side of the Salinas Valley, the potential for seawater moving inland increases. Enhancing recharge in these areas would be beneficial in reducing seawater intrusion while lowering flood risk and erosion damage. The article reviews potential strategies to increase infiltration of rainwater during winter storms thereby recharging the underlying aquifer.