Earthquake probabilities in the San Francisco Bay region: 2002-2031
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Badlands are common arid and semiarid landscapes long recognized in slope development and erosion rate studies by preeminent geomorphologists including Gilbert, Davis, and Schumm. The trip described here will examine in detail Quaternarystrata and landscape evolution in arguably the most famous badlands, the White River Badlands of South Dakota, which were pivotal during development of vertebrate paleontology in North America. Geologists have collected fossils from the White River Group there nearly every field season since the mid-1800s; however, until recently, little work was reported on the extensively exposed Quaternary strata. The White River Badlands are also a proposed dust source for the widespread PeoriaLoess of the Central Great Plains. The research highlighted on this trip includes (1) luminescence and radiocarbon ages from late Pleistocene through Holocene eolian sand, (2) radiocarbon ages from Holocene eolian cliff-top deposits, (3) luminescenceages from late Pleistocene fluvial silts, (4) radiocarbon ages of late Holocene fluvial silts, and (5) cosmogenic ages on ventifacts from the adjoining upper prairie. These new studies will facilitate discussions, including (1) late Quaternary paleoenvironments,(2) late Quaternary fluvial incision rates and episodes, (3) up-wind sediment supply of late Quaternary nonglaciogenic loess, (4) landscape evolution spanning late Pleistocene tableland through late Holocene sod table development, and (5) modern erosion-pedimentation rates.
In response to a request by the National Oceanic and Atmospheric Administration (NOAA) for computing tsunami propagations in the western Pacific, Eric Geist asked Willie Lee for assistance in providing parameters of earthquakes which may be future tsunami sources. The U.S. Geological Survey (USGS) Tsunami Source Working Group (TSWG) was initiated in August 2005. An ad hoc group of diverse expertise was formed, with Steve Kirby as the leader. The founding members are: Rick Blakely, Eric Geist, Steve Kirby, Willie Lee, George Plafker, Dave Scholl, Roland von Huene, and Ray Wells. Half of the founding members are USGS emeritus scientists. A report was quickly completed because of NOAA's urgent need to precalculate tsunami propagation paths for early warning purposes. It was clear to the group that much more work needed to be done to improve our knowledge about tsunami sources worldwide. The group therefore started an informal research program on tsunami sources and meets irregularly to share ideas, data, and results. Because our group activities are open to anyone, we have more participants now, including, for example, Harley Benz and George Choy (USGS, Golden, Colo.), Holly Ryan and Stephanie Ross (USGS, Menlo Park, Calif.), Hiroo Kanamori (Caltech), Emile Okal (Northwestern University), and Gerard Fryer and Barry Hirshorn (Pacific Tsunami Warning Center, Hawaii). To celebrate the fifth anniversary of the TSWG, a workshop is being held in the Auditorium of Building 3, USGS, Menlo Park, on July 19-20, 2010 (Willie Lee and Steve Kirby, Conveners). All talks (except one) will be video broadcast. The first tsunami source workshop was held in April 2006 with about 100 participants from many institutions. This second workshop (on a much smaller scale) will be devoted primarily to recent work by the USGS members. In addition, Hiroo Kanamori (Caltech) will present his recent work on the 1960 and 2010 Chile earthquakes, Barry Hirshorn and Stuart Weinstein (Pacific Tsunami Warning Center) will present their work on tsunami warning, and Rick Wilson (California Geological Survey) will display three posters on tsunami studies by him and his colleagues.
Mauna Loa, the largest volcano on Earth, has erupted 33 times since written descriptions became available in 1832. Some eruptions began with only brief seismic unrest, while others followed several months to a year of increased seismicity. Once underway, its eruptions can produce lava flows that may reach the sea in less than 24 hours, severing roads and utilities. For example, lava flows erupted from the Southwest Rift Zone (SWRZ) in 1950 advanced at an average rate of 9.3 km per hour, and all three lobes reached the ocean within approximately 24 hours (Finch and Macdonald, 1953). Near the eruptive vents, the flows must have traveled even faster. In terms of eruption frequency, pre-eruption warning, and rapid flow emplacement, Mauna Loa poses an enormous volcanic-hazard threat to the Island of Hawai‘i. Volcanic hazards on Mauna Loa may be anticipated, and risk substantially mitigated, by documenting the past activity to refine our knowledge of the hazards and by alerting the public and local government officials of our findings and their implications for hazards assessments and risk. From the geologic record, we may deduce several generalized facts about the geologic history of the Northeast Rift Zone (NERZ). The middle to uppermost segments of the rift zone were more active in the past 4,000 years than the lower portion of the rift zone. This may be due to buttressing of the lower east rift zone by Mauna Kea and Kīlauea volcanoes. The historical flows that erupted on the north side of the rift zone advanced toward Hilo. This flank of the volcano may be more vulnerable to inundation. Lockwood (1990) noted that the vents of historical activity are migrating to the south. The volcano appears to have a self-regulating mechanism that evenly distributes long-term activity across its flanks. The geologic record also supports this notion; the time prior to the historical period (Age Group 1, pre-A.D. 1832 to 1,000 yrs B.P.; orange units) is dominated by activity on the south side of the NERZ. Although most Mauna Loa eruptions begin in the summit area at the 12,000-ft elevation (Lockwood and Lipman, 1987), the central-southeast flank has not been the source of any activity. All flows originated from the summit or the upper reaches of the Northeast Rift Zone (NERZ) or the Southwest Rift Zone (SWRZ). The NERZ was the source of eight flank eruptions since 1843. The NERZ extends from the 13,680-ft-high summit towards Hilo (population ~60,000; second-largest city in State of Hawaii). The northern portion of the map area is built entirely on flows erupted from the NERZ. The SWRZ extends from the summit towards Kalae (South Point) at sea level. The southern portion of the map area is built entirely on flows erupted from the SWRZ. The map area extends from the 10,350 -ft elevation on Mauna Loa’s east flank toward the Hawaii Volcanoes National Park and the town of Volcano (population approx. 2,000) in the northeast. At the south boundary of the map area is the town of Pāhala (population approx. 900). This map includes areas adjacent to and downslope of the NERZ and regions east of and directly downslope of Moku‘āweoweo, Mauna Loa’s summit caldera. The map encompasses 506 km 2 of the southeast flank (fig. 1) of Mauna Loa from 10,350 -ft elevation to sea level. The map of the central-southeast flank of Mauna Loa shows the distribution and relations of volcanic and surficial sedimentary deposits separated into 15 age groups ranging from a period greater than 50,000 yr B.P. to A.D. 1984. It incorporates previously reported work published in generalized small-scale maps (Lockwood and Lipman, 1987; Lockwood, 1995; Wolfe and Morris, 1996). This map is the second in a series of five maps that will cover Mauna Loa volcano. See SIM 2932-A at https://doi.org/10.3133/sim2932A . NOTE: Map sheet 1 contains lines and type with overprint. This feature may be turned on or off in the Adobe Acrobat page display preferences.
About this volume The Williston Basin, which includes parts of Montana, North Dakota, and South Dakota in the United States, has been a leading domestic oil and gas producing area. To better understand the potential effects of energy development on environmental resources in the Williston Basin, the U.S. Geological Survey, in cooperation with the Bureau of Land Management, and in support of the needs identified by the Bakken Federal Executive Group (consisting of representatives from 13 Federal agencies and Tribal groups), began work to synthesize existing information on science topics to support management decisions related to energy development. This report is divided into four chapters (A–D). Chapter A provides an executive summary of the report and principal findings from chapters B–D. Chapter B provides a brief compilation of information regarding the history of energy development, physiography, climate, land use, demographics, and related studies in the Williston Basin. Chapter C synthesizes current information about water resources, identifies potential effects from energy development, and summarizes water resources research and information needs in the Williston Basin. Chapter D summarizes information about ecosystems, species of conservation concern, and potential effects to those species from energy development in the Williston Basin.
In 1986, the U.S. Geological Survey began a National Water-Quality Assessment program to (1) provide nationally consistent descriptions of the current status of water quality for a large, diverse, and geographically distributed part of the Nation's surface- and ground-water resources; (2) define, where possible, trends in water quality; and (3) identify and describe the relations of both status and trends in water quality to natural factors and the history of land use and land- and waste-management activities. The program is presently in a pilot phase that will test and modify, as necessary, concepts and approaches in preparation for possible full implementation of the program in the future. The upper Illinois River basin is one of four basins selected to test the concepts and approaches of the surface-water-quality element of the national program. The basin drains 10,949 square miles of Illinois, Indiana, and Wisconsin. Three principal tributaries are the Kankakee and Des Plaines Rivers that join to form the Illinois River and the Fox River. Land use is predominantly agricultural; about 75 percent of the basin is cultivated primarily for production of corn and soybeans. About 13 percent of the basin is urban area, most of which is located in the Chicago metropolitan area. The population of the basin is about 7 million. About 6 million people live in the Des Plaines River basin. Many water-quality issues in the upper Illinois River basin are related to sediment, nutrients, potentially toxic inorganic and organic constituents, and to water-management practices. Occurrence of sediment and the chemical constituents in the rivers and lakes within the basin has the potential to adversely affect the water's suitability for aquatic life, recreation, or, through the consumption of fish, human health. The upper Illinois River basin project consists of five major activities. The first activity--analysis of existing information and preparation of a report that describes recent water-quality conditions and trends--is currently underway. The second activity--fixed-station water-quality sampling at eight stations--began in April 1987 and will last at least 3 years. Water-quality data collected at these stations will be used to determine the frequency of occurrence of constituent concentrations, their annual and seasonal loads, and time trends in concentrations for a selected number of constituents. The third activity will be synoptic water-quality studies. Each study will involve sampling many sites at specific flow conditions and for selected water-quality constituents. Information gained from these studies will supplement informa tion gained from fixed-station sampling. A synoptic study of streambed sediments is tentatively planned for the summer of 1987 to describe the occurrence and distribution of trace elements in the basin. The fourth activity will consist of one or more topical subbasin or river-reach studies. The purpose of such studies is to better define certain water-quality conditions in specific areas and gain an understanding of the processes affecting the observed conditions. The fifth activity is the preparation of reports that will describe results from each of the first four activities. Quality assurance and coordination are being provided at both the national and pilot-project levels. A technical quality-assurance plan that addresses all aspects of sample collection, analysis, and reporting is being prepared at the national level. This plan will be appended as needed at the pilot-project level. A National Coordinating Work Group that functions under the auspices of the Interagency Advisory Committee on Water Data and the Advisory Committee on Water Data for Public Use has been established at the national level. A local liaison committee consisting of representatives from Federal, State, and local agencies has been established to enhance communication and to ensure that the scientific information produced by the
The Community for Data Integration (CDI) continued to experience success in fiscal year 2015. The CDI community members have been sharing, learning, and collaborating through monthly forums, workshops, working groups, and funded projects. In fiscal year 2015, CDI coordinated 10 monthly forums with 16 different speakers from the U.S. Geological Survey and external partners; funded 11 collaborative projects; and hosted an in-person, four-day workshop, which attracted 168 (134 in-person and 34 remote) data practitioners, data providers, and data consumers from across the USGS, academia, industry, and other government agencies. The Citizen Science, Connected Devices, Data Management, Semantic Web, and Tech Stack Working Groups continued to accomplish great things in fiscal year 2015. These working groups were major stakeholders in planning the 2015 CDI Workshop; they continued developing solutions to pressing challenges, and they brought in speakers throughout the year for more focused presentations and discussions. Additionally, a new working group formed during the 2015 CDI Workshop—the Earth-Science Themes Working Group.
For the past 36 years, Bulletin 17B, published by the Interagency Committee on Water Data in 1982, has guided flood-frequency analyses in the United States. During this period, much has been learned about both hydrology and statistical methods. In keeping with the tradition of periodically updating the Bulletin 17B guidelines in light of advances in our understanding and methods, the Hydrologic Frequency Analysis Work Group (HFAWG) was charged by the Subcommittee on Hydrology (SOH) of the Advisory Committee on Water Information (ACWI) to consider possible updates to Bulletin 17B. The purpose of this report is to consider the statistical performance of possible revisions to Bulletin 17B procedures. Of particular interest are procedures designed to accommodate more general forms of flood information. The concern is how the proposed procedures would affect the precision, accuracy and robustness of flood-frequency estimates. The investigations reported here focus on techniques for the following: incorporating information related to historical flooding that occurred outside the period of systematic streamgaging; and identification of potentially influential low floods (PILFs). The proposed changes, which mostly involve generalizing Bulletin 17B’s method-of-moments procedures by using the Expected Moments Algorithm (EMA), are relatively modest, at least in the sense that they would not affect the main features of Bulletin 17B. The proposed methods include the following: continued use of the log-Pearson Type 3 (LP3) distribution; continued use of the Method-of-Moments fitting method applied to the logarithms of annual-peak-flow data; and a generalization of the Grubbs-Beck test used in Bulletin 17B to identify low outliers. The new multiple Grubbs-Beck test is sensitive to multiple PILFs. The hydrological literature already provides extensive support for the theory behind the proposed changes. The remaining question is practical: How well do the proposed methods perform under typical and realistic conditions and, specifically, with difficult records occasionally encountered in practice? In order to answer these questions, the HFAWG commissioned the work reported here. The following four major sets of results are provided: Monte Carlo simulations of fitting procedures employing data drawn from simulated LP3 populations; Monte Carlo simulations of fitting procedures employing data drawn from non-LP3 populations that were selected to reflect likely deviations of flood series from LP3 distributions, based on the experience of HFAWG members; a direct comparison of the fitted LP3 distributions for 82 real “test sites” identified by an independent data group as both “typical” and “challenging” for flood-frequency estimation; and simulations of fitting procedures using records obtained by resampling with replacement from the longest of the 82 test-site records. Collectively, these studies provide a reasonably comprehensive, valid, and robust assessment of the properties of the Bulletin 17B methods and proposed alternatives. The experiments and analysis indicate that the flood quantile estimators, proposed as a revision of Bulletin 17B, do the following: perform generally as well as, and in some cases much better than, Bulletin 17B estimators in terms of the mean square error of flood quantiles estimates; allow for incorporation and efficient statistical treatment of broader classes of flood-frequency data and information, including historical information, binomial data and interval data; and generally confirm studies and the theoretical findings reported in the hydrological literature that would support use of updated estimation procedures that have been developed since Bulletin 17B was published.
This report presents a map and database of Quaternary deposits and liquefaction susceptibility for the urban core of the San Francisco Bay region. It supercedes the equivalent area of U.S. Geological Survey Open-File Report 00-444 (Knudsen and others, 2000), which covers the larger 9-county San Francisco Bay region. The report consists of (1) a spatial database, (2) two small-scale colored maps (Quaternary deposits and liquefaction susceptibility), (3) a text describing the Quaternary map and liquefaction interpretation (part 3), and (4) a text introducing the report and describing the database (part 1). All parts of the report are digital; part 1 describes the database and digital files and how to obtain them by downloading across the internet. The nine counties surrounding San Francisco Bay straddle the San Andreas fault system, which exposes the region to serious earthquake hazard (Working Group on California Earthquake Probabilities, 1999). Much of the land adjacent to the Bay and the major rivers and streams is underlain by unconsolidated deposits that are particularly vulnerable to earthquake shaking and liquefaction of water-saturated granular sediment. This new map provides a consistent detailed treatment of the central part of the 9-county region in which much of the mapping of Open-File Report 00-444 was either at smaller (less detailed) scale or represented only preliminary revision of earlier work. Like Open-File Report 00-444, the current mapping uses geomorphic expression, pedogenic soils, inferred depositional environments, and geologic age to define and distinguish the map units. Further scrutiny of the factors controlling liquefaction susceptibility has led to some changes relative to Open-File Report 00-444: particularly the reclassification of San Francisco Bay mud (Qhbm) to have only MODERATE susceptibility and the rating of artificial fills according to the Quaternary map units inferred to underlie them (other than dams - adf). The two colored maps provide a regional summary of the new mapping at a scale of 1:200,000, a scale that is sufficient to show the general distribution and relationships of the map units but not to distinguish the more detailed elements that are present in the database. The report is the product of cooperative work by the National Earthquake Hazards Reduction Program (NEHRP) and National Cooperative Geologic Mapping Program of the U.S. Geological Survey, William Lettis and & Associates, Inc. (WLA), and the California Geological Survey. An earlier version was submitted to the U.S. Geological Survey by WLA as a final report for a NEHRP grant (Witter and others, 2005). The mapping has been carried out by WLA geologists under contract to the NEHRP Earthquake Program (Grant 99-HQ-GR-0095) and by the California Geological Survey.
In the summer of 2022, the U.S. Fish & Wildlife Service and partners successfully completed the first single-year, aerial photo survey of sea otters across the entire Southeast stock of northern sea otters. This document presents the latest findings from the 2022 Southeast Alaska Sea Otter Survey, providing up-to-date information regarding occupancy, abundance and carrying capacity. We collected two independent data streams of sea otter observations during the survey using novel image sensor technologies for marine wildlife surveys and recently developed statistical methods. We calculated an abundance estimate of 22,359 (95% Bayesian credible interval: 19,595, 25,290, CV = 0.064) sea otters. Based on the these results, the population size of the Southeast stock of northern sea otters is still increasing and below the estimated carrying capacity for the region of 48,083 (95% Bayesian credible interval: 40,575, 58,570) sea otters. Results from this report include the first updated abundance estimates for the Southeast stock of sea otters in 10 years, which will help inform stakeholders from across the region and addresses the top priority identified by the 2019 Southeast Sea Otter Stakeholder Working Group.
What are the most important challenges facing solid Earth science today and over the next two decades? And what is the best approach for NASA, in partnership with other agencies, to address those challenges? A new report, Living on a Restless Planet, provides a blueprint for answering these questions. The top priority for a new spacecraft mission in the area of solid Earth science over the next 5 years, according to this report, is a satellite dedicated to Interferometric Synthetic Aperture Radar (InSAR). At the request of NASA, the Solid Earth Science Working Group (SESWG) developed a strategy for the highest priority objectives in solid Earth science for the space agency over the next 25 years. The strategy addresses six challenges that are of fundamental scientific importance, have strong implications for society, and are amenable to substantial progress through a concerted series of scientific observations from space.
Public water systems provide potable water for the public's use. The Safe Drinking Water Act amendments of 1996 required States to prepare a source-water susceptibility assessment (SWSA) for each public water system (PWS). States were required to determine the source of water for each PWS, the origin of any contaminant of concern (COC) monitored or to be monitored, and the susceptibility of the public water system to COC exposure, to protect public water supplies from contamination. In Texas, the Texas Commission on Environmental Quality (TCEQ) was responsible for preparing SWSAs for the more than 6,000 public water systems, representing more than 18,000 surface-water intakes or groundwater wells. The U.S. Geological Survey (USGS) worked in cooperation with TCEQ to develop the Source Water Assessment Program (SWAP) approach and methodology. Texas' SWAP meets all requirements of the Safe Drinking Water Act and ultimately provides the TCEQ with a comprehensive tool for protection of public water systems from contamination by up to 247 individual COCs. TCEQ staff identified both the list of contaminants to be assessed and contaminant threshold values (THR) to be applied. COCs were chosen because they were regulated contaminants, were expected to become regulated contaminants in the near future, or were unregulated but thought to represent long-term health concerns. THRs were based on maximum contaminant levels from U.S. Environmental Protection Agency (EPA)'s National Primary Drinking Water Regulations. For reporting purposes, COCs were grouped into seven contaminant groups: inorganic compounds, volatile organic compounds, synthetic organic compounds, radiochemicals, disinfection byproducts, microbial organisms, and physical properties. Expanding on the TCEQ's definition of susceptibility, subject-matter expert working groups formulated the SWSA approach based on assumptions that natural processes and human activities contribute COCs in quantities that vary in space and time; that increased levels of COC-producing activities within a source area may increase susceptibility to COC exposure; and that natural and manmade conditions within the source area may increase, decrease, or have no observable effect on susceptibility to COC exposure. Incorporating these assumptions, eight SWSA components were defined: identification, delineation, intrinsic susceptibility, point- and nonpoint-source susceptibility, contaminant occurrence, area-of-primary influence, and summary components. Spatial datasets were prepared to represent approximately 170 attributes or indicators used in the assessment process. These primarily were static datasets (approximately 46 gigabytes (GB) in size). Selected datasets such as PWS surface-water-intake or groundwater-well locations and potential source of contamination (PSOC) locations were updated weekly. Completed assessments were archived, and that database is approximately 10 GB in size. SWSA components currently (2011) are implemented in the Source Water Assessment Program-Decision Support System (SWAP-DSS) computer software, specifically developed to produce SWSAs. On execution of the software, the components work to identify the source of water for the well or intake, assess intrinsic susceptibility of the water- supply source, assess susceptibility to contamination with COCs from point and nonpoint sources, identify any previous detections of COCs from existing water-quality databases, and summarize the results. Each water-supply source's susceptibility is assessed, source results are weighted by source capacity (when a PWS has multiple sources), and results are combined into a single SWSA for the PWS.'SWSA reports are generated using the software; during 2003, more than 6,000 reports were provided to PWS operators and the public. The ability to produce detailed or summary reports for individual sources, and detailed or summary reports for a PWS, by COC or COC group was a unique capability of SWAP-DSS. In 2004, the TCEQ began a rotating schedule for SWSA wherein one-third of PWSs statewide would be assessed annually, or sooner if protection-program activities deemed it necessary, and that schedule has continued to the present. Cooperative efforts by the TCEQ and the USGS for SWAP software maintenance and enhancements ended in 2011 with the TCEQ assuming responsibility for all tasks.
The primary goal of the biology characterization breakout group was to identify the strategies, tools, data priorities, and key partnerships needed to conduct baseline biological characterizations of deep-sea benthic environments across the U.S. EEZ in the Pacific. Discussions focused primarily on priorities for the characterization of deep-water (>200-meter depths) benthic biological communities; however, the group also emphasized that such characterizations need to be linked to efforts to characterize the overlying water column. The group was tasked with identifying how to prioritize exploration and characterization efforts, including how to identify priority geographic areas and specific methodologies needed to execute exploration activities. The expert community that provided input included representatives from various stakeholder groups actively working on deep-sea issues across the Pacific, including researchers and managers from government agencies, academic institutions, nongovernmental institutions, and the private sector. This report provides a summary of specific guidance identified as key for the successful exploration of deep-sea benthic habitats within the U.S. EEZ in the Pacific, as well as in adjacent international waters.
The 2018 annual report of the U.S. Geological Survey Woods Hole Coastal and Marine Science Center summarizes the work of the center, as well as the work of each of its science groups, highlights accomplishments of 2018, and includes a list of publications published in 2018. This product allows readers to gain a general understanding of the focus areas of the center’s scientific research and learn more about specific projects and progress made throughout 2018, all while enjoying applicable photos taken in the field and of various models, maps, and web pages.
The objective of this report is to provide a record of some of the goals and accomplishments of the coal resource investigations of the U. S. Geological Survey for 1977. Successful completion of these goals will aid the Nation in the years ahead because proper usage of coal resource data may lessen economic displacements resulting from the energy shortage. This report is concerned only with one mineral fuel -- coal -- and only with coal resource investigations in the Geologic Division of the U. S. Geological Survey. Other divisions involved with coal or coal-related work are the Conservation, Water Resources, and Topographic Divisions. It is one of a series of reports on the energy resource studies conducted by the Geological Survey that provide a public record of the objectives, activities, and accomplishments of these programs. Similar reports have been prepared on oil and gas, oil shale, uranium, thorium, and energy-related industrial minerals. This report includes descriptions of the program, each sub-element of the program, individual projects, and a selected list of program publications from 1970-76. It also describes how the program is responsive to Presidential pronouncements and Congressional mandates. The program is cooperative with several Federal bureaus, many state agencies, universities, and industry. This coordination assures that the program supplements the work of these interested groups and is not duplicative. A scientific program such as the coal resource investigations is difficult for the non-involved person to understand solely from the existing reports on various studies made in the program. This report provides an explanation that the scientist, decision maker, personnel of other government agencies, and the layman can use to relate various activities and to gain a better understanding of the relation of coal to the Nation's requirements for energy and of the importance of a carefully planned program on this energy resource.
The purpose of this report is to provide a glossary of selected terms for saturated and unsaturated flow and related processes involved in transport of contaminants in the subsurface. The glossary contains five tables. Table 1 is a list of parameters with associated symbols and units. Tables 2 to 5 are conversion charts. The original manuscript was prepared by Thomas J. Nicholson, U.S. Nuclear Regulatory Commission. It was subsequently examined by the Ground-Water Glossary Working Group and experts within and outside the Federal Government, whose recommendations were accommodated where appropriate in the glossary. It is hoped that the glossary will aid in the communications between soil scientists, hydrologists, and hydrogeologists. The terms defined in the glossary were selected after an extensive survey of glossaries and reports in the areas of (1) ground-water geology, hydraulics, and chemistry, (2) soil-water physics and chemistry, (3) contaminant transport, (4) unsaturated-zone hydrology, (5) chemistry and transport of solutes, and (6) ground-water quality. Some of the definitions have been modified for clarity from a variety of technical sources. Where more than one definition appears for the selected term, the first one was determined by the working group to be the most appropriate general definition, followed by other, more specialized, definitions. Some terms and definitions are not currently in use by all agencies; however, they are included in the glossary because they can be found in the literature. The reader is encouraged to consult with the original source cited for more explanatory comments. Additional regulatory definitions, which are underlined and are taken directly from the Code of Federal Regulations (CFR) and Federal laws (USC), were added following review by the various Federal agencies in May 1986. The definitions and conversion charts are from two principal sources provided herein. The first is the 11Glossary11 compiled by A. I. Johnson in the 1981 report by the American Society of Testing and Materials titled Permeability and Groundwater Contaminant Transport. The second is Manu a 1 40, 11Ground-water Management, 11 produced by the American Society of Civil Engineers in 1985.
(Hartwell) This report is prepared primarily to account for work conducted and products delivered in FY 2022 by GCMRC and to inform the Technical Work Group of science conducted by GCMRC and its cooperators in support of the Glen Canyon Dam Adaptive Management Program (GCDAMP). It includes a summary of accomplishments, modifications to work plans, results, and recommendations related to projects included in GCMRC’s FY 2021-23 Triennial Work Plan. This work was done to support the 11 resource goals identified in the Glen Canyon Dam Long-Term Experimental and Management Plan (LTEMP) Environmental Impact Statement and Record of Decision (Table 1).