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A Conjunctive Use Model for the Tule Groundwater Sub-Basin Area in the Southern-Eastern San Joaquin Valley, California

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A Conjunctive Use Model for the Tule Groundwater Sub-Basin Area in the Southern-Eastern San Joaquin Valley, California
U.S. Bureau of Reclamation (USBR) | February 4, 2003...
Summary
The Tule groundwater sub-basin is an agriculturally-intensive area located in the eastern-central part of the southern San Joaquin Valley, California. Urban and agricultural...

The Tule groundwater sub-basin is an agriculturally-intensive area located in the eastern-central part of the southern San Joaquin Valley, California. Urban and agricultural stakeholders in the Tule sub-basin depend on a combination of imported surface water and pumped groundwater to meet their water de- mands. The water service districts there receive surface water deliveries from the Friant Unit of the Central Valley Project (CVP) (United States Bureau of Reclamation), the State Water Project (SWP) (California Department of Water Resources), the Kings River (United States Army Corps of Engineers), or the Success Reservoir (United States Army Corps of Engineers). All of these surface water sources develop their supplies from run-off and snow melt in the foothills and watersheds of the Sierra Nevada mountain range. The state of California is prone to recurring droughts, some lasting several years. During drought periods, irrigated agriculture depends more heavily on groundwater pumping as surface water supplies are generally less available. To buffer the effects of drought, districts in the Tule sub-basin have cooperatively managed their surface water and groundwater resources conjunctively. During a normal to wet year, excess available surface water supplies (e.g. releases for flood control) are used by some districts to recharge their groundwater reservoirs. However, a prolonged multi-year drought invariably leads to an increased dependence on groundwater pumping and overdraft of the groundwater sub-basin storage. In addition to climate variability, changes in future surface water supplies may also occur due to the passage of the Central Valley Project Improvement Act of 1992, which mandates that 400,000 acre-feet per year of CVP water be released from the Friant Unit into the San Joaquin River for restoration purposes.

To better understand the impacts of irrigated agriculture, fluctuating surface water supplies, and groundwater pumping practices on water levels and groundwater storage in the Tule sub-basin area, we developed a GIS-based con- junctive use model to study them. The study area is 541,580 acres in size and contains the entire Tule groundwater sub-basin and parts of the Kaweah and Tulare Lake groundwater sub-basins. The incorporated land in the study area is divided into 26 water service districts: 21 irrigation, water, or public utility districts; 2 major cities; 2 private contractors; and 1 water company. These districts are either completely or partially located within the study area. The study area is further delineated into 9,114 individual land units from a 1985 land use survey of Tulare County. Agriculture is the largest land use, compris- ing 72% of the study area. Native and urban land use comprise 22% and 4% of the study area, respectively. Semi-agricultural and special conditions (i.e. fallow) land use each comprise 1%. Twelve crops account for 95% of the area under agricultural production. Cotton, grain & grass hay, citrus, vineyards, and alfalfa individually represent 20.3, 18.6, 13.6, 13, and 10.3% of the total productive acreage, respectively.

Surface water supplies are distributed to the districts and ultimately to the individual land units by a surface water supply system. The surface water supply system in the model is divided into two parts: 1) an inter-district surface water channel network, and 2) an intra-district surface water distribution system. The inter-district channel network consists of the explicitly modeled source and diversion channels which import surface water into the study area and deliver it to individual districts. The intra-district distribution system con- sists of the implicitly modeled district channels (e.g. laterals, ditches, canals, farm turnouts) which deliver surface water to individual land units within each district.

The conjunctive use model consists of three loosely-coupled sub-models: 1) a surface water supply (SWS) model, 2) an unsaturated zone water budget (UZWB) model, and 3) a groundwater flow model. The base period of the study covers the fiscal water years of 1970-99. The purpose of the SWS model is to calculate the surface water balance for the source and diversion channels in the inter-district channel network. For each modeled surface water channel, the SWS model computes surface water deliveries from it to each district and conveyance losses from it due to evaporation and channel seepage. The primary model outputs are monthly surface water deliveries to each district and monthly seepage rates from modeled channels. The surface water deliveries became input for the UZWB model. The channel seepage became input for the groundwater flow model as localized aquifer recharge. The allocation of surface water within each district, via the implicitly modeled intra-district surface water distribution system, is estimated by the UZWB model.

The total imported surface water for 1970-99 from the CVP and the Success Reservoir are 13,329,262 and 4,653,501 acre-feet (af), respectively. The SWP and the Kings River imported the lesser amounts of 88,625 and 7,332 af, respec- tively. Annual CVP diversions varied from 125,970 af in 1977 to 679,298 af in 1993 with a 30-year annual average of 444,309 af. The Tule River and Pioneer Ditch both receive regulated releases from Success Reservoir. Tule River annual imports varied from 11,034 af in 1977 to 607,154 af in 1983 while the Pioneer Ditch varied from 3,445 af in 1973 to 5,874 af in 1990. The total natural runoff from the Deer Creek and White River from 1970-99 were 703,444 and 219,098 af, respectively. Deer Creek runoff varied from 4,082 af in 1992 to 103,716 af in 1983 while the White River runoff varied from 422 af in 1977 to 37,985 af in 1998.

From 1970-99, a total of 15 million af of surface water was applied by the service districts in the study area. The applied surface water varied from a low of 135,482 af in 1977 to a high of 708,293 af in 1996. The Lower Tule River Ir- rigation District and the Delano-Earlimart Irrigation District together account for 59% of the total applied surface water while occupying approximately 40% of the incorporated area in the study area. Over the 30-year base period, an estimated total of 3.5 million af of seepage conveyance loss occurred in all sur- face water channels. Seepage in the Tule River, Deer Creek, and White River accounted for 85% of the total seepage. Total annual seepage varied from a low of 8,128 af in 1977 to 467,084 af in 1983.

The UZWB model then calculates the monthly water storage changes in the soil root zone and deep vadose zone of each land unit, where the land unit is the UZWB model scale of resolution. It also models the intra-district surface water distribution system by estimating the monthly allocation of surface water to individual land units within each district. The main model outputs were the recharge to the unconfined aquifer from surface applied water and precipitation, and the groundwater pumping demand from the unconfined and confined aquifers. The recharge and groundwater pumping rates became input for the groundwater flow model.

The total annual agricultural and urban consumptive use ranged from 865,800 af in 1970 to 1,246,700 af in 1999. The estimated total pumping ranged from 148,100 af in 1978 to 570,000 af in 1990. As expected, pumping was heaviest during the droughts of 1975-77 and 1987-92, and lightest during the wet years of 1973, 1978, 1982-83, 1995, and 1998. Precipitation totals varied from 177,800 af in 1990 to 974,400 af in 1998. Diffuse recharge from surface applied water ranged from 64,800 af in 1992 to 350,100 af in 1983.

The net aquifer recharge for the entire study area was computed by ag- gregating the aquifer recharge and groundwater pumping of each land unit to this scale and adding the contribution to aquifer recharge from channel seepage. The monthly net recharge was then summed to produce a cumulative annual net recharge from 1970 to each fiscal water year from 1971-99. The water balance computed for the entire study area neglects horizontal groundwater inflows and outflows through its vertical boundaries. Groundwater fluxes undoubtedly exist along these boundaries. However, net fluxes are likely small in comparison to the total changes in storage due to vertical stresses applied to the entire study area (e.g. groundwater pumping, evapotranspiration, applied surface water, channel seepage). Horizontal groundwater flow on the inter-land unit and inter-district scales is expected to be more significant. For computing a total water balance, however, we made the simplifying assumption that the study area behaves as a relatively closed system where the net horizontal groundwater inflows through its vertical boundaries are small. Invoking this assumption, we then use the cumulative net recharge as an estimate of the cumulative groundwater storage change in the aquifer system. Ideally, verification of these estimates is performed by comparing them with an objective measure of the study area aquifer storage changes. However, changes in groundwater storage are not directly observable and must always be estimated using non-direct measures. As such, an objec- tive measure for verification does not exist. As an alternative, we compare the water balance model results with those produced by the water-table fluctuation (WTF) method.

The trends in cumulative annual groundwater storage changes computed from the water balance and the WTF method from 1970-99 were quite similar. The minimum and maximum differences between them were 2,450 af (1980) and 752,387 af (1991), respectively. From 1970, the maximum amount of ground- water accumulation occurred in the spring of 1987 with the WTF method and the water balance estimating positive storage changes of 1,146,286 and 898,128 af, respectively. The maximum groundwater overdraft occurred in 1993 with the WTF method and the water balance estimating negative storage changes of 1,610,210 and 1,218,566 af, respectively. The 1987 and 1993 fiscal water years marked the beginning and ending of a major 6-year drought in California, respectively.

Finally, the groundwater flow model calculates the changes in water levels in the aquifer system subject to transient groundwater recharge and pump- ing stresses. A post-processing routine calculates the cumulative groundwater storage changes over each district and the entire study area for each stress pe- riod. An automated calibration of the groundwater flow model was performed to refine the conceptual model of the hydrogeology and to estimate the spa- tial distributions of the aquifer system horizontal hydraulic conductivity. The calibration period of the groundwater flow model is 1970-85 and the validation period is 1986-99.

Three different conceptual models of the aquifer system horizontal hydraulic conductivity, Kh, structure were evaluated in the calibration process: 1) Khas an exponential function of the specific yield, Sy, distribution, 2) Kh as a linear function of the saturated hydraulic conductivity of the soil survey map- ping units, and 3) division of the model domain into square zones of uniform size. The models were calibrated against both spatially distributed hydraulic head targets and cumulative groundwater storage change targets for seven of the largest districts. The discretization of the model domain into uniform square zones provided the most robust Kh structure and produced the most reason- able estimates of hydraulic head and district groundwater storage changes from the three conceptual models over the 1971-85 calibration period. The calibrated model was then used to compute the annual net inter-district groundwater fluxes between adjacent districts. In general, groundwater flux directions were con- sistent with the large-scale hydraulic gradients. Annual inter-district net fluxes between adjacent districts ranged from negligibly small ( < 100 af) to as much as 80,000 af (e.g. net flux from Lower Tule River ID to Pixley ID). Net inter-district fluxes were generally a function of the local transmissivity, the length of the shared border between adjacent districts, and the differences in their surface water supplies.

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Analysis of Groundwater Basin Yield, Upper Santa Clara River Groundwater Basin, East Subbasin, Los Angeles County, California

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Analysis of Groundwater Basin Yield, Upper Santa Clara River Groundwater Basin, East Subbasin, Los Angeles County, California
Castaic Lake Water Agency, Newhall County Water District, Santa Clarita Water | August 15, 2005...
Summary
This report presents an evaluation of the long-term sustainability of existing groundwater management practices in the Santa Clarita Valley, located in northwestern Los Angeles County,...
This report presents an evaluation of the long-term sustainability of existing groundwater management practices in the Santa Clarita Valley, located in northwestern Los Angeles County, California. The groundwater system in the Santa Clarita Valley is identified by the California Department of Water Resources (DWR) as the Santa Clara River Valley Groundwater Basin, East Subbasin (Basin No. 4-4.07) and lies within the DWR-designated Upper Santa Clara River Hydrologic Area. Groundwater in the basin is pumped from a shallow Alluvial Aquifer and deeper groundwater resources that are present in an older, underlying unit called the Saugus Formation. Most groundwater pumping is by the local water purveyors (the Upper Basin Water Purveyors [herein referred to as the Purveyors1]) for municipal uses (in the range of approximately 23,000 to 28,000 acre-feet per year [AF/yr] in recent years), with some continuing pumping by private landowners, primarily for irrigation uses (approximately 15,000 to 16,000 AF/yr in recent years). The Purveyors also have access to other sources of water, including imported State Water Project (SWP) water, groundwater banking outside the basin, recycled water, short-term water exchanges, and dry-year water purchase programs (Luhdorff & Scalmanini Consulting Engineers [LSCE], 2005a). The water management practices of the Purveyors call for maximizing the use of Alluvial Aquifer and imported water during years of normal or above-normal availability of these supplies, and limiting the use of the Saugus Formation during these periods, then temporarily increasing Saugus Formation pumping during years when supplemental imported water supplies are significantly reduced because of drought conditions.

The evaluation of the Purveyors’ current groundwater management practices has been performed using a detailed numerical groundwater flow model of the basin. The model, called the Santa Clarita Valley Groundwater Model (Regional Model), simulates the occurrence and flow of groundwater, including its interaction with streams in the area. The Regional Model has been developed for the Purveyors as a tool for the analysis of groundwater management options in the context of future water demands and water supply conditions in the valley. Among the objectives in developing the model were

(1) to be able to evaluate the long-term sustainability (yield) of the Alluvial and Saugus aquifer systems under a range of existing and potential future water resource management conditions, and

(2) to facilitate general management of water quantity and water quality issues. Figure 1-1 is a map showing the area simulated by the model (tables and figures are located at the end of each section).

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Conjunctive Management and Groundwater Storage (Resource Management Strategy)
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Conjunctive Management and Groundwater Storage (Resource Management Strategy)
California Department of Water Resources (DWR) | July 29, 2016...
Summary
Conjunctive management or conjunctive use refers to the coordinated and planned use and management of both surface water and groundwater resources to maximize...
Conjunctive management or conjunctive use refers to the coordinated and planned use and management of both surface water and groundwater resources to maximize the availability and reliability of water supplies in a region to meet various management objectives. Surface water and groundwater resources typically differ significantly in their availability, quality, management needs, and development and use costs. Managing both resources together, rather than in isolation, allows water managers to use the advantages of both resources for maximum benefit. Conjunctive management thus involves the efficient use of both resources through the planned and managed operation of a groundwater basin and a surface water storage system combined through a coordinated conveyance infrastructure.

Water is stored in the groundwater basin that is planned to be used later by intentionally recharging the basin when excess water supply is available, for example, during years of above-average surface water supply or through the use of recycled water. The necessity and benefit of conjunctive water management are apparent when surface water and groundwater are hydraulically connected. Well-planned conjunctive management that prevents groundwater depletion by maintaining baseflow to streams and support for ecosystem services not only increases the reliability and the overall amount of water supply in a region, but also provides other benefits such as flood management, environmental water use, and water quality improvement.

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Economic and Water Supply Effects of Ending Groundwater Overdraft in California’s Central Valley
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Economic and Water Supply Effects of Ending Groundwater Overdraft in California’s Central Valley
San Francisco Estuary and Watershed Science | March 1, 2016...
Summary
Surface water and groundwater management are often tightly linked, even when linkage is not intended or expected. This link is especially common in...
Surface water and groundwater management are often tightly linked, even when linkage is not intended or expected. This link is especially common in semi-arid regions, such as California. This paper summarizes a modeling study on the effects of ending long-term overdraft in California’s Central Valley, the state’s largest aquifer system. The study focuses on economic and operational aspects, such as surface water pumping and diversions, groundwater recharge, water scarcity, and the associated operating and water scarcity costs. This analysis uses CALVIN, a hydro-economic optimization model for California’s water resource system that suggests operational changes to minimize net system costs for a given set of conditions, such as ending long-term overdraft. Based on model results, ending overdraft might induce some major statewide operational changes, including large increases to Delta exports, more intensive conjunctive-use operations with increasing artificial and in-lieu recharge, and greater water scarcity for Central Valley agriculture. The statewide costs of ending roughly 1.2 maf yr of groundwater overdraft are at least $50 million per year from additional direct water shortage and additional operating costs. At its worst, the costs of ending Central Valley overdraft could be much higher, perhaps comparable to the recent economic effects of drought. Driven by recent state legislation to improve groundwater sustainability, ending groundwater overdraft has important implications statewide for water use and management, particularly in the Sacramento–San Joaquin Delta. Ending Central Valley overdraft will amplify economic pressure to increase Delta water exports rather than reduce them, tying together two of California’s largest water management problems.

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Geology, Ground-Water Hydrology, Geochemistry, and Ground-Water Simulation of the Beaumont and Banning Storage Units, San Gorgonio Pass Area, Riverside County, California
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Geology, Ground-Water Hydrology, Geochemistry, and Ground-Water Simulation of the Beaumont and Banning Storage Units, San Gorgonio Pass Area, Riverside County, California
U.S. Geological Survey (USGS) | December 14, 2006...
Summary
Ground-water has been the only source of potable water supply for residential, industrial, and agricultural users in the Beaumont and Banning storage units...
Ground-water has been the only source of potable water supply for residential, industrial, and agricultural users in the Beaumont and Banning storage units of the San Gorgonio Pass area, Riverside County, California. Ground-water levels in the Beaumont area have declined as much as 100 feet between the early 1920s and early 2000s, and numerous natural springs have stopped flowing. In 1961, the San Gorgonio Pass Water Agency (SGPWA) entered into a contract with the California State Department of Water Resources to receive 17,300 acre-feet per year of water to be delivered by the California State Water Project (SWP) to supplement natural recharge. Currently (2005), a pipeline is delivering SWP water into the area, and the SGPWA is artificially recharging the ground-water system using recharge ponds located along Little San Gorgonio Creek in Cherry Valley with the SWP water. In addition to artificial recharge, SGPWA is considering the direct delivery of SWP water for the irrigation of local golf courses and for agricultural supply in lieu of ground-water pumpage. To better understand the potential hydrologic effects of different water-management alternatives on ground-water levels and movement in the Beaumont and Banning storage units, existing geohydrologic and geochemical data were compiled, new data from a basin-wide ground-water level and water-quality monitoring network were collected, monitoring wells were installed near the Little San Gorgonio Creek recharge ponds, geohydrologic and geochemical analyses were completed, and a ground-water flow simulation model was developed.

The San Gorgonio Pass area was divided into several storage units on the basis of mapped or inferred faults. This study addresses primarily the Beaumont and Banning storage units. The geologic units in the study area were generalized into crystalline basement rocks and sedimentary deposits. The younger sedimentary deposits and the surficial deposits are the main water-bearing deposits in the San Gorgonio Pass area. The water-bearing deposits were divided into three aquifers: (1) the perched aquifer, (2) the upper aquifer, and (3) the lower aquifer based on lithologic and downhole geophysical logs.

Natural recharge in the San Gorgonio Pass area was estimated using INFILv3, a deterministic distributed- parameter precipitation-runoff model. The INFILv3 model simulated that the potential recharge of precipitation and runoff in the Beaumont and Banning storage units was about 3,710 acre-feet per year and that the potential recharge in 28 sub-drainage basins upstream of the storage units was about 6,180 acre-feet per year.

The water supply for the Beaumont and Banning storage units is supplied by pumping ground water from wells in the Canyon (Edgar and Banning Canyons), Banning Bench, Beaumont, and Banning storage units. Total annual pumpage from the Beaumont and Banning storage units ranged from about 1,630 acre-feet in 1936 to about 20,000 acre-feet in 2003. Ground-water levels declined by as much as 100 feet in the Beaumont storage unit from 1926–2003 in response to ground-water pumping of about 450,160 acre-feet during this period.

Since ground-water development began in the San Gorgonio Pass area, there have been several sources of artificial recharge to the basin including return flow from applied water on crops, golf courses, and landscape; septic-tank seepage; and infiltration of storm runoff diversions and imported water into recharge ponds. Return flow from applied water and septic-tank seepage was estimated to reach a maximum of about 8,100 acre-feet per year in 2003. Owing to the great depth of water in much of study area (in excess of 150 feet), the return flow and septic-tank seepage takes years to decades to reach the water table.

Stable-isotope data indicate that the source of ground-water recharge was precipitation from storms passing through the San Gorgonio Pass as opposed to runoff from the higher altitudes of the San Bernardino Mountains. In addition, these data indicate that little if any of the ground water in the fractured crystalline rocks flows across the Banning Fault into the Beaumont storage unit. Tritium concentrations indicate that little to no recharge has reached the water table since 1952 in most areas of the Beaumont and Banning storage units. In general, the uncorrected carbon-14 ages of ground water sampled from wells in the Beaumont, Banning, and surrounding storage units ranged from about 400 to 17,500 years before present. The older water was sampled in southeastern part of Beaumont storage unit and in the Banning storage unit, and ranged from 1,900 to 17,500 years before present.

To better understand the dynamics of ground-water flow and the potential effects of water-level changes resulting from artificial recharge in the San Gorgonio Pass area, a regional-scale, numerical ground-water flow model was developed using MODFLOW-96. This model will be used by water managers to help manage the ground-water resources in the San Gorgonio Pass area. Results of the steady-state simulation indicate that the total inflow rate, or recharge, was about 6,590 acre-feet per year with about 3,710 acre-feet per year from areal recharge, about 2,670 acre-feet per year from mountain-front recharge, and about 210 acre-feet per year from the surrounding older sedimentary deposits. The simulated water budget for 1926–2003 indicates that of the total simulated volume of water pumped from the aquifer (450,160 acre-feet), about 50 percent was derived from depletion of ground-water storage (222,660 acre-feet), about 21 percent was derived from the reduction of underflow to the Cabazon and San Timoteo storage units (about 96,280 acre-feet), about 19 percent was derived from a reduction of ground-water outflow to the stream channels draining the San Timoteo storage unit (about 86,030 acre-feet), about 8 percent was derived from irrigation return flows and septic-tank seepage (about 36,780 acre-feet), and about 2 percent was derived from an increase in ground-water underflow from the surrounding older sedimentary deposits (about 8,410 acre-feet).

The calibrated ground-water flow model was used to simulate the effects of four water-management scenarios being considered by SGPWA for the period 2004–13. In general, the results of the water-management scenarios indicate that artificial recharge in the Little San Gorgonio Creek recharge ponds primarily benefits the area north of the Cherry Valley Fault. For the scenario that used SWP water in lieu of ground water for golf course irrigation and for agricultural use, hydraulic heads increased by about 50 feet. None of the water-management scenarios significantly benefited the Banning storage unit.

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Hydrogeologic Controls and Geochemical Indicators of Groundwater Movement in the Niles Cone and Southern East Bay Plain Groundwater Subbasins, Alameda County, California

Characterization of storage capacities and hydraulic properties of the complex aquifers and the structural and stratigraphic controls on groundwater movement aids in optimal storage and recovery of recharged water and provides information on the ability of aquifers shared by different water management agencies to fulfill competing storage and extraction demands.

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Hydrogeologic Controls and Geochemical Indicators of Groundwater Movement in the Niles Cone and Southern East Bay Plain Groundwater Subbasins, Alameda County, California
U.S. Geological Survey (USGS) | January 1, 2018...
Summary
Beginning in the 1970s, Alameda County Water District began infiltrating imported water through ponds in repurposed gravel quarries at the Quarry Lakes Regional...
Beginning in the 1970s, Alameda County Water District began infiltrating imported water through ponds in repurposed gravel quarries at the Quarry Lakes Regional Park, in the Niles Cone groundwater subbasin, to recharge groundwater and to minimize intrusion of saline, San Francisco Bay water into freshwater aquifers. Hydraulic connection between distinct aquifers underlying Quarry Lakes allows water to recharge the upper aquifer system to depths of 400 feet below land surface, and the Deep aquifer to depths of more than 650 feet. Previous studies of the Niles Cone and southern East Bay Plain groundwater subbasins suggested that these two subbasins may be hydraulically connected. Characterization of storage capacities and hydraulic properties of the complex aquifers and the structural and stratigraphic controls on groundwater movement aids in optimal storage and recovery of recharged water and provides information on the ability of aquifers shared by different water management agencies to fulfill competing storage and extraction demands. The movement of recharge water through the Niles Cone groundwater subbasin from Quarry Lakes and the possible hydraulic connection between the Niles Cone and the southern East Bay Plain groundwater subbasins were investigated using interferometric synthetic aperture radar (InSAR), water-chemistry, and isotopic data, including tritium/helium-3, helium-4, and carbon-14 age-dating techniques.

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Hydrogeology and Water Supply of Salinas Valley
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Hydrogeology and Water Supply of Salinas Valley
Monterey County Water Resources Agency (MCWRA) | June 15, 1995...
Summary
The Monterey County Water Resources Agency (MCWRA) convened a panel of 10 geologists, hydrogeologists, and engineers familiar with Salinas Valley ground water basin...
The Monterey County Water Resources Agency (MCWRA) convened a panel of 10 geologists, hydrogeologists, and engineers familiar with Salinas Valley ground water basin to attempt to reach agreement on the basic physical characteristics of the basin, and the surface and ground water flow within the basin. Agreement on the completeness and accuracy of existing data and previous hydrogeological studies was seen as an important first step in identifying and implementing a technically sound solution acceptable to the public that would stop seawater intrusion that began some 60 years ago.

Mike Armstrong, General Manager of MCWRA, instructed the panel to review and, if possible, reach consensus on the hydrogeological characteristics of the basin, define clearly the water resources problems in the basin, and determine surface water and ground water flow within the basin. We were not requested to discuss specific local projects or political and institutional aspects of the problems.

The panel met in a closed-door session in Monterey on May 24 and 25, 1995. The session was closed to the public and the press to enable the panelists to discuss and explore ideas and opinions freely without worrying about statements, questions, and hypotheses being repeated out of context.

Members of the panel believe the process worked very well. This report presents our findings, conclusions, and recommendations. We were able to achieve more than our original scope of work. There was remarkable unanimity of opinion on our understanding of the physical characteristics of the basin, the hydrologic system, the interaction between surface water and ground water, and definition of the specific ground water problems in the basin. In summary, the facts we agreed upon point so compellingly toward an already identified regional solution to the Valley's ground water resources problems that the panel has included a potential solution. We have included a strong recommendation in this White Paper for implementing that regional solution.

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Hydrologic Modeling Goals and Objectives for Yolo County

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Hydrologic Modeling Goals and Objectives for Yolo County
Water Resources Association of Yolo County, California Department of Water Resources (DWR) | May 16, 2002...
Summary
The Water Resources Association of Yolo County (WRA) has entered into a Memorandum of Understanding (MOU) with the California Department of Water Resources (DWR)...
The Water Resources Association of Yolo County (WRA) has entered into a Memorandum of Understanding (MOU) with the California Department of Water Resources (DWR) to cooperatively investigate conjunctive use opportunities in Yolo County. As part of the MOU, DWR is assisting the WRA to develop goals and objectives for a combined groundwater and surface water model of Yolo County, including a modeling strategy. As DWR’s contractor, WRIME, Inc., in collaboration with the DWR, WRA, and other consultants with modeling experience/knowledge about Yolo County, conducted the modeling assessment study.

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Lower Mill Creek Watershed Conjunctive Use Project: Tehama County, California
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Lower Mill Creek Watershed Conjunctive Use Project: Tehama County, California
California Department of Water Resources (DWR) | November 18, 2008...
Summary
In 1920, the Tehama County Superior Court of the State of California adjudicated entitlements to all Mill Creek flow below 203 cubic feet...
In 1920, the Tehama County Superior Court of the State of California adjudicated entitlements to all Mill Creek flow below 203 cubic feet per second (cfs). As such, water right holders on Mill Creek legally divert a significant portion of the surface water flow for agricultural beneficial use.

During certain times of the year, especially during dry or critically dry years, the agricultural demand for surface water can reduce Mill Creek flow and expose in-stream barriers to fish migration. Fishery experts recognize Mill Creek as a high priority stream for the protection and enhancement of Chinook salmon spawning habitat.

Mill Creek surface water diverters currently participate in a long-term cooperative management plan to help provide sufficient flow for fish migration while also maintaining irrigation supplies and the recognition of surface water rights. As part of these efforts, Mill Creek water users participate in water lease and groundwater exchange programs designed to increase in-stream flow during critical spring and fall fish migration periods.

Along with other entities, the Department of Water Resources (DWR) plans to establish methods of monitoring and studying fish passage, assessing agricultural water use efficiency, and examining the potential for additional use of groundwater as opposed to use of surface water diversions in the Lower Mill Creek watershed.

This report provides a background of the geology and hydrogeology in the Lower Mill Creek watershed area, a detailed discussion of the groundwater resources, and an overview of the potential for conjunctive use of surface water and groundwater resources. It also provides recommendations for additional groundwater monitoring and potentially favorable locations for production well installation associated with possible future conjunctive use programs.

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Monterey County Groundwater Management Plan
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Monterey County Groundwater Management Plan
Monterey County Water Resources Agency | May 17, 2006...
Summary
In 1992, California State Legislature adopted the Groundwater Management Act (California Water Code Part 2.7, §10753), originally enacted as Assembly Bill (AB) 3030...
In 1992, California State Legislature adopted the Groundwater Management Act (California Water Code Part 2.7, §10753), originally enacted as Assembly Bill (AB) 3030 and amended by Senate Bill (SB) 1938 in 2002. The Groundwater Management Act provided the authority to prepare groundwater management plans and encouraged local agencies to work cooperatively to manage groundwater resources within their jurisdictions and groundwater basins.

Monterey County Water Resources Agency (MCWRA), recognizing that management of its natural water resources is critical to ensuring a long-term sustainable and reliable good quality water supply, has prepared this Groundwater Management Plan (GWMP). The purpose of the GWMP is to provide a comprehensive overview of the Salinas Valley Groundwater Basin and to recommend various management strategies for the basin. Specifically, this document provides the framework for the management of groundwater resources in the Salinas Valley Groundwater Basin (exclusive of the Seaside and Paso Robles subareas) and acts as a guidance document for future groundwater projects.

While this edition of the GWMP focuses on the Salinas Valley Groundwater Basin, MCWRA is responsible for the management of the water resources for all of Monterey County. Future GWMP versions will incorporate the additional groundwater basins in the County. This document has been prepared in accordance with existing regulations as outlined in the California Water Code (as referenced above) and was prepared in coordination with local agencies and interested residents through public outreach activities.

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A Conjunctive Use Model for the Tule Groundwater Sub-Basin Area in the Southern-Eastern San Joaquin Valley, California

A Conjunctive Use Model for the Tule Groundwater Sub-Basin Area in the Southern-Eastern San Joaquin Valley, California

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Analysis of Groundwater Basin Yield, Upper Santa Clara River Groundwater Basin, East Subbasin, Los Angeles County, California

Analysis of Groundwater Basin Yield, Upper Santa Clara River Groundwater Basin, East Subbasin, Los Angeles County, California

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Conjunctive Management and Groundwater Storage (Resource Management Strategy)

Conjunctive Management and Groundwater Storage (Resource Management Strategy)

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Economic and Water Supply Effects of Ending Groundwater Overdraft in California’s Central Valley

Economic and Water Supply Effects of Ending Groundwater Overdraft in California’s Central Valley

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Geology, Ground-Water Hydrology, Geochemistry, and Ground-Water Simulation of the Beaumont and Banning Storage Units, San Gorgonio Pass Area, Riverside County, California

Geology, Ground-Water Hydrology, Geochemistry, and Ground-Water Simulation of the Beaumont and Banning Storage Units, San Gorgonio Pass Area, Riverside County, California

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Hydrogeologic Controls and Geochemical Indicators of Groundwater Movement in the Niles Cone and Southern East Bay Plain Groundwater Subbasins, Alameda County, California

Hydrogeologic Controls and Geochemical Indicators of Groundwater Movement in the Niles Cone and Southern East Bay Plain Groundwater Subbasins, Alameda County, California

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Hydrogeology and Water Supply of Salinas Valley

Hydrogeology and Water Supply of Salinas Valley

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Hydrologic Modeling Goals and Objectives for Yolo County

Hydrologic Modeling Goals and Objectives for Yolo County

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Lower Mill Creek Watershed Conjunctive Use Project: Tehama County, California

Lower Mill Creek Watershed Conjunctive Use Project: Tehama County, California

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Monterey County Groundwater Management Plan

Monterey County Groundwater Management Plan

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