Download or read book Integrated Hydrologic Model of Pajaro Valley Santa Cruz and Monterey Counties California written by and published by . This book was released on 2014 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing population, agricultural development (including shifts to more water-intensive crops), and climate variability are placing increasingly larger demands on available groundwater resources in the Pajaro Valley, one of the most productive agricultural regions in the world. This study provided a refined conceptual model, geohydrologic framework, and integrated hydrologic model of the Pajaro Valley. The goal of this study was to produce a model capable of being accurate at scales relevant to water management decisions that are being considered in the revision and updates to the Basin Management Plan (BMP). The Pajaro Valley Hydrologic Model (PVHM) was designed to reproduce the most important natural and human components of the hydrologic system and related climatic factors, permitting an accurate assessment of groundwater conditions and processes that can inform the new BMP and help to improve planning for long-term sustainability of water resources. Model development included a revision of the conceptual model of the flow system, reevaluation of the previous model transformed into MODFLOW, implementation of the new geohydrologic model and conceptual model, and calibration of the transient hydrologic model. The conceptual model identified inflows and outflows that include the movement and use of water from natural and human components. The groundwater flow system is characterized as a layered geologic sedimentary system through which downward flow is driven by the combined effects of the application of irrigation water at the land surface and the pumping of groundwater from deeper in the system. Overall, groundwater meets most of the agricultural demand in the initial part of the growing season, augmented by precipitation during wet winter and spring seasons. In addition, the amount of groundwater used for irrigation varies from year to year in response to climate variation and can increase dramatically in dry years. Data on agricultural pumpage is a major component of simulated outflow that was previously unavailable; therefore, a coupled farm-process model was used to estimate historical pumpage for Pajaro Valley by subregion (water-balance subregions) as well as the delivery of surface water to and from the Harkins Slough Aquifer-Storage-and-Recovery System (HS-ASR) and related Coastal Distribution System (CDS) since 2002. The new, integrated hydrologic model includes new water-balance subregions; delineation of natural, municipal, and agricultural land use; streamflow networks; regions of tile drains; and, the groundwater flow system. The redefinition of the geohydrologic framework and incorporation into the simulation revealed the importance of the confining units at the base of the alluvial deposits and between the upper and lower Aromas Sand for regional groundwater flow. The PVHM model, using MODFLOW with the Farm Process (MF-FMP2), is capable of being accurate at seasonal to interannual time frames and subregional to valley-wide spatial scales for the assessment of the groundwater hydrologic budget for water years 1964-2009, as well as potential assessment of the BMP components and sustainability analysis of conjunctive use. The model provides a good representation of the regional flow system and the use and movement of water throughout the valley. Simulated changes in storage over time show that, prior to the 1984-92 dry period, significant withdrawals from storage occurred only during drought years. Since about 1993, growers in the Pajaro Valley have shifted to more water intensive crops, such as strawberries, bushberries, and vegetable row crops, as well as making additional rotational plantings, which have increased demand on limited groundwater resources. Simulated groundwater flow indicates that vertical hydraulic gradients between horizontal layers fluctuate and even reverse in several parts of the basin as recharge and pumpage rates change seasonally and annually. The majority of recharge predominantly enters the Alluvial aquifer system, and along with pumpage and the largest fractions of storage depletion, occurs in the inland regions. Coastal inflow as seawater intrusion replaces much of the potential storage depletion in the coastal regions. The simulated long-term imbalance between inflows and outflows indicates overdraft of the groundwater basin averaging about 12,950 acre-feet per year (acre-ft/yr) over the 46-year period of water years (1964-2009). Annual overdraft varies considerably from year to year, depending on land use, pumpage, and climate conditions. Climatically driven factors can affect inflows, outflows, and water use by as much as a factor of two between wet and dry years. Coastal inflows and outflows vary by year and by aquifer; the net coastal inflow, or seawater intrusion, ranges from about 1,000 to more than 6,000 acre-ft/yr. Maps of simulated and measured water-level elevations indicate regions with water levels below sea level in the alluvium and Aromas layers. Ongoing expansion of local hydrologic monitoring networks indicates the importance of these networks to the understanding of changes in groundwater flow, streamflow, and streamflow infiltration. In particular, the monitoring of streamflow, groundwater pumpage, and groundwater levels throughout the valley not only indicates the state of the resources, but also provides valuable information for model calibration and for model-based evaluation of management actions. The HS-ASR was simulated for the years 2002-09, and replaced about about 1,290 acre-ft of coastal pumpage. This was combined with the simulation of additional 6,200 acre-ft of deliveries from supplemental wells, recycled water, and city connection deliveries through the CDS that also supplanted some coastal pumpage. Total simulated deliveries were 7,350 acre-ft of the 7,500 acre-ft of reported deliveries for the period 2002-09. The completed CDS should be capable of delivering about 8.8 million cubic meters (7,150 acre-ft) of water per year to coastal farms within the Pajaro Valley, if all the local supply components were fully available for this purpose. This would represent about 15 percent of the 48,300 acre-ft (59.6 million cubic meters) average agricultural pumpage for the period 2005 to 2009. Combined with the potential capture and reuse of some of the return flows and tile-drain flows, this could represent an almost 70 percent reduction of average overdraft for the entire valley and a large part of the coastal pumpage that induces seawater intrusion.
Download or read book Water resources Investigations Report written by and published by . This book was released on 1988 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pajaro Valley Water Management Agency Revised Basin Management Project written by and published by . This book was released on 2004 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pajaro Valley Water Management Agency Revised Basin Management Plan written by and published by . This book was released on 2003 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pajaro River Flood Control Project written by United States. Army. Corps of Engineers and published by . This book was released on 1970 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Saline Water Intrusion Pajaro Valley written by Harvey O. Banks and published by . This book was released on 1975 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Documentation of Model Input and Output Values for the Geohydrology and Mathematical Simulation of the Pajaro Valley Aquifer System Sanat Cruz and Monterey Cou Nties California written by Hugh T. Mitten and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flood Control Alternatives for Pajaro Valley Pajaro River Salispuedes Corralitos Creek written by and published by . This book was released on 1974 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrologic Models and Analysis of Water Availability in Cuyama Valley California written by and published by . This book was released on 2014 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Changes in population, agricultural development practices (including shifts to more water-intensive crops), and climate variability are placing increasingly larger demands on available water resources, particularly groundwater, in the Cuyama Valley, one of the most productive agricultural regions in Santa Barbara County. The goal of this study was to produce a model capable of being accurate at scales relevant to water management decisions that could be considered in the evaluation of the sustainable water supply. The Cuyama Valley Hydrologic Model (CUVHM) was designed to simulate the most important natural and human components of the hydrologic system, including components dependent on variations in climate, thereby providing a reliable assessment of groundwater conditions and processes that can inform water users and help to improve planning for future conditions. Model development included a revision of the conceptual model of the flow system, construction of a precipitation-runoff model using the Basin Characterization Model (BCM), and construction of an integrated hydrologic flow model with MODFLOW-One-Water Hydrologic Flow Model (MF-OWHM). The hydrologic models were calibrated to historical conditions of water and land use and, then, used to assess the use and movement of water throughout the Valley. These tools provide a means to understand the evolution of water use in the Valley, its availability, and the limits of sustainability. The conceptual model identified inflows and outflows that include the movement and use of water in both natural and anthropogenic systems. The groundwater flow system is characterized by a layered geologic sedimentary sequence that--in combination with the effects of groundwater pumping, natural recharge, and the application of irrigation water at the land surface--displays vertical hydraulic-head gradients. Overall, most of the agricultural demand for water in the Cuyama Valley in the initial part of the growing season is supplied by groundwater, which is augmented by precipitation during wet winter and spring seasons. In addition, the amount of groundwater used for irrigation varies from year to year in response to climate variation and can increase dramatically in dry years. Model simulation results, however, also indicated that irrigation may have been less efficient during wet years. Agricultural pumpage is a major component to simulated outflow that is often poorly recorded. Therefore, an integrated, coupled farm-process model is used to estimate historical pumpage for water-balance subregions that evolved with the development of groundwater in the Valley from 1949 through 2010. The integrated hydrologic model includes these water-balance subregions and delineates natural, municipal, and agricultural land use; streamflow networks; and groundwater flow systems. The redefinition of the geohydrologic framework (including the internal architecture of the sedimentary units) and incorporation of these units into the simulation of the regional groundwater flow system indicated that faults have compartmentalized the alluvial deposits into subregions, which have responded differently to regional groundwater flow, locations of recharge, and the effects of development. The Cuyama Valley comprises nine subregions grouped into three regional zones, the Main, Ventucopa Uplands, and Sierra Madre Foothills, which are fault bounded, represent different proportions of the three alluvial aquifers, and have different water quality. The CUVHM uses MF-OWHM to simulate and assess the use and movement of water, including the evolution of land use and related water-balance regions. The model is capable of being accurate at annual to interannual time frames and at subregional to valley-wide spatial scales, which allows for analysis of the groundwater hydrologic budget for the water years 1950-2010, as well as potential assessment of the sustainable use of groundwater. Simulated changes in storage over time showed that significant withdrawals from storage generally occurred not only during drought years (1976-77 and 1988-92) but also during the early stages of industrial agriculture, which was initially dominated by alfalfa production. Since the 1990s, agriculture has shifted to more water-intensive crops. Measured and simulated groundwater levels indicated substantial declines in selected subregions, mining of groundwater that is thousands to tens of thousands of years old, increased groundwater storage depletion, and land subsidence. Most of the recharge occurs in the upland regions of Ventucopa and Sierra Madre Foothills, and the largest fractions of pumpage and storage depletion occur in the Main subregion. The long-term imbalance between inflows and outflows resulted in simulated overdraft (groundwater withdrawals in excess of natural recharge) of the groundwater basin over the 61-year period of 1949-2010. Changes in storage varied considerably from year to year, depending on land use, pumpage, and climate conditions. Climatically driven factors can greatly affect inflows, outflows, and water use by more than a factor of two between wet and dry years. Although precipitation during inter-decadal wet years previously replenished the basin, the water use and storage depletion have lessened the effects of these major recharge events. Simulated and measured water-level altitudes indicated the presence of large areas where depressed water levels have resulted in large desaturated zones in the younger and Older Alluvium layers in the Main-zone subregions. The results of modeled projection of the base-case scenario 61 years into the future indicated that current supply-and-demand are unsustainable and will result in additional groundwater-level declines and related storage depletion and land subsidence. The reduced-supply and reduced-demand projections reduced groundwater storage depletion but may not allow for sustainable agriculture under current demands, agricultural practices, and land use.
Download or read book OECD Studies on Water Sustainable Management of Water Resources in Agriculture written by OECD and published by OECD Publishing. This book was released on 2010-03-15 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report calls on policy makers to recognise the issues at stake in water resource management in agriculture and gives them the tools to do so, offering a wealth of information on recent trends and the outlook for water resource use in agriculture.
Download or read book Water resources Data Network Evaluation for Monterey County California Phase 2 written by William E. Templin and published by . This book was released on 1996 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1989 with total page 1296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Managing California s Water written by Ellen Hanak and published by Public Policy Instit. of CA. This book was released on 2011 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Working Paper Environmental Evaluation of Pajaro River Flood Control Project Santa Cruz and Monterey Counties California written by United States. Army. Corps of Engineers and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geohydrology of Recharge and Seawater Intrusion in the Pajaro Valley Santa Cruz and Monterey Counties California written by R. T. Hanson and published by . This book was released on 2003 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flood Control and Allied Purposes for Pajaro River Basin Santa Clara Santa Cruz and Monterey Counties California written by United States. Army. Corps of Engineers and published by . This book was released on 1965 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1989 with total page 1310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
