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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 217 records · Page 12Linked to original sources
USGS2000

Landsat 5/Landsat 7 underfly cross-calibration experiment

There was a one-time opportunity to obtain nearly coincident coverage from both Landsat 5 and Landsat 7 as Landsat 7 drifted to its final orbital position during the initialization and verification phase following launch. During the underfly period, Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data were collected using the U.S Landsat 7 ground station network and the solid-state recorder, while agreements were established with Space Imaging/EOSAT and various international ground stations to collect corresponding Landsat 5 Thematic Mapper (TM) data. Approximately 750 coincident scenes were collected during the underfly from 1-3 June 1999. Underfly data are intended to play a major role in developing cross-calibrations to bridge the results derived from historical Landsat 5 TM data with research performed with current Landsat 7 ETM+ data. The purpose of this paper is to provide an overview of the underfly experiment, and to provide some early comparative results between Landsat 5 and 7 data sets. Initial results indicate that products produced using TM and ETM+ data are very similar.

Conference Paper↗
USGS2010

Importance of record length with respect to estimating the 1-percent chance flood

U.S. Geological Survey (USGS) streamflow gages have been established in every State in the Nation, Puerto Rico, and the Trust Territory of the Pacific Islands. From these st reamflow records, estimates of the magnitude and frequency of floods are often developed and used to design transportation and water- conveyance structures to protect lives and property, and to determine flood-insurance rates. Probably the most recognizable flood statistic computed from USGS stream gaging records is the 1- percent (%) chance flood; better known has the 100-year flood. By definition, this is a flood that has a 1% chance of occurring in any given year. The 1% chance flood is a statistical estimate that can be significantly influenced by length of record and extreme flood events captured in that record. Consequently, it is typically recommended that flood statistics be updated on some regular interval such as every 10 years. This paper examines the influence of record length on the 1% chance flood for the Broad River in Georgia and the substantial difference that can occur in the estimate based on record length and the hydrologic conditions under which that record was collected.

Conference Paper↗
USGS2017

Numerical simulations of sand production in interbedded hydrate-bearing sediments during depressurization

Geomechanical behavior of hydrate-bearing sediments during gas production is complex, involving changes in hydrate-dependent mechanical properties. When interbedded clay layers are present, the complexity is more pronounced because hydrate dissociation tends to occur preferentially in the sediments adjacent to the clay layers due to clay layers acting as a heat source. This would potentially lead to shearing deformation along the sand/clay contacts and may contribute to solid migration, which hindered past field-scale gas production tests. This paper presents a near-wellbore simulation of sand/clay interbedded hydrate-bearing sediments that have been subjected to depressurization and discusses the effect of clay layers on sand production.

Conference Paper↗
USGS2006

Uncertainty management, spatial and temporal reasoning, and validation of intelligent environmental decision support systems

There are inherent open problems arising when developing and running Intelligent Environmental Decision Support Systems (IEDSS). During daily operation of IEDSS several open challenge problems appear. The uncertainty of data being processed is intrinsic to the environmental system, which is being monitored by several on-line sensors and off-line data. Thus, anomalous data values at data gathering level or even uncertain reasoning process at later levels such as in diagnosis or decision support or planning can lead the environmental process to unsafe critical operation states. At diagnosis level or even at decision support level or planning level, spatial reasoning or temporal reasoning or both aspects can influence the reasoning processes undertaken by the IEDSS. Most of Environmental systems must take into account the spatial relationships between the environmental goal area and the nearby environmental areas and the temporal relationships between the current state and the past states of the environmental system to state accurate and reliable assertions to be used within the diagnosis process or decision support process or planning process. Finally, a related issue is a crucial point: are really reliable and safe the decisions proposed by the IEDSS? Are we sure about the goodness and performance of proposed solutions? How can we ensure a correct evaluation of the IEDSS? Main goal of this paper is to analyse these four issues, review some possible approaches and techniques to cope with them, and study new trends for future research within the IEDSS field.

Conference Paper↗
USGS2002

Effects of water use diversion regulation and conservation on sediemtn transport with comparisons from the United States

Too much sediment and too little water are related problems in China’s Yellow River Basin. Sediment yield in the basin averages about 2,100 t/(km 2 ·a), greatest is of the world’s large rivers although the Yellow River ranks 31st in mean flow. A quarter of the sediment deposited in the 780-km lower reach, causing bed levels to rise an average of a meter per decade wang and other. Sediment aggradation along this reach is concentrated between dikes, resulting in average river-bed elevations 5 m higher, and at Xinxiang as much as 10 m higher, than surrounding bottomlands. The dikes, which have breached nearly 1,600 times in the last 24 centuries, reduce the threat of flooding for 85-million people on 120,000 km 2 in five provinces of northeastern China (Decun, undated). This paper addresses some environmental and social factors related to this problem, and provides descriptions of two United States rivers that exhibit some analogous responses, albeit not to the extent of those associated with the Yellow River, “China’s Sorrow”.

Yellow River↗
USGS1997

Two-dimensional habitat modeling in the Yellowstone/Upper Missouri River system

This study is being conducted to provide the aquatic biology component of a decision support system being developed by the U.S. Bureau of Reclamation. In an attempt to capture the habitat needs of Great Plains fish communities we are looking beyond previous habitat modeling methods. Traditional habitat modeling approaches have relied on one-dimensional hydraulic models and lumped compositional habitat metrics to describe aquatic habitat. A broader range of habitat descriptors is available when both composition and configuration of habitats is considered. Habitat metrics that consider both composition and configuration can be adapted from terrestrial biology. These metrics are most conveniently accessed with spatially explicit descriptors of the physical variables driving habitat composition. Two-dimensional hydrodynamic models have advanced to the point that they may provide the spatially explicit description of physical parameters needed to address this problem. This paper reports progress to date on applying two-dimensional hydraulic and habitat models on the Yellowstone and Missouri Rivers and uses examples from the Yellowstone River to illustrate the configurational metrics as a new tool for assessing riverine habitats.

Conference Paper↗
USGS2002

Mars Geodesy/Cartography Working Group recommendations on Mars cartographic constants and coordinate systems

NASA's Mars Geodesy/Cartography Working Group (MGCWG), established in 1998 and chaired since 2000 by one of us (TCD), consists of leading researchers in planetary geodesy and cartography at such diverse institutions as JPL, NASA Ames and Goddard Centers, Purdue and Ohio State Universities, Malin Space Science Systems, the German Center for Aerospace Research DLR, and the US Geological Survey, as well as representatives of the current and future Mars mission teams that are the customers for Mars maps. The purpose of the group is the coordinate the activities of the many agencies active in Mars geodesy and cartography in order to minimize redundant effort and ensure that the products needed by mission customers are generated. A specific objectives has been to avoid repeating the experience of the 1970s-80s, when competing researchers produced geodetic control solutions and maps of Mars that were mutually inconsistent. To this end, the MGCWG has recently assembled a set of preferred values for Mars cartographic constants, based on the best available data. These values have been transmitted to the International Astronomical Union and appear in the report of the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites as the officially recommended constants for Mars (Seidelmann et al., 2002). The MGCWG has also recommended to NASA that the USGS adopt the IAU-approved coordinate system of planetocentric latitude and east longitude for future maps of Mars, in the place of the (also IAU-approved) planetographic system with west longitude positive. This recommendation has recently been approved by NASA. In this paper we present the preferred values for Mars cartographic constants with discussion of the process by which they were derived, then discuss the rationale and implications of the use of east/planetocentric coordinates in future Mars maps.

Conference Paper↗
USGS2019

Near-field remote sensing of Alaskan Rivers

The U.S. Geological Survey (USGS) Geomorphology and Sediment Transport Laboratory (GSTL), in collaboration with the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL), acquired remotely sensed data from several Alaskan rivers in 2017 and 2018 with the goal of developing a methodology for measuring streamflow from a helicopter. CRREL operates a custom airborne lidar system that can be deployed in a helicopter-based pod (HeliPod). Data were collected with the HeliPod near existing USGS streamflow information stations on the Knik, Matanuska, Chena, and Salcha Rivers in both 2017 and 2018. Sites on the Tanana and Snow Rivers were added in 2018. In 2018, the HeliPod was modified to accommodate both a thermal infrared and a visible camera. The cameras were integrated with the flight management software to simultaneously acquire imagery with lidar. The Global Navigation Satellite System (GNSS) and inertial measurement unit (IMU) in the HeliPod were used to compute trajectories with precise position and orientation information needed for image orthorectification. The HeliPod sensors provide data for measuring river channel characteristics. Lidar can map the elevation of the water surface and thus be used to measure water-surface slopes and return intensity can be used to delineate the extent of the wetted river channel. Various approaches are currently being evaluated to estimate surface flow velocity from visible and thermal image time series. In this paper, we examine and compare water-surface elevation returns and slopes derived from the HeliPod lidar and found good agreement with measurements made using conventional field-based techniques.

Alaska↗
USGS2022

Update on the Center for Engineering Strong-Motion Data (CESMD)

he Center for Engineering Strong-Motion Data (CESMD), an internationally utilized joint center of the U.S. Geological Survey (USGS) and the California Geological Survey (CGS), provides a unified access point for earthquake strong-motion records and station metadata from the CGS California Strong-Motion Instrumentation Program (CSMIP), the USGS National Strong-Motion Project (NSMP), the USGS Advanced National Seismic System (ANSS), and other affiliates. The CESMD works closely with the ANSS and with the Consortium of Organizations for Strong-Motion Observation Systems (COSMOS) to engage with strong-motion networks in the U.S. and other countries to receive, process, and post records. The CESMD has recently developed new tools to facilitate access to strong-motion data and metadata for use in post-earthquake response and scientific research applications. The Center provides raw and processed strong-motion data via its Engineering Data Center (EDC) and the Virtual Data Center (VDC) web portals, currently hosting more than 60,000 records with peak ground accelerations greater than 0.1% g, from over 3,000 earthquakes. This short paper provides updates of the available strong-motion data, station metadata, recent enhancements and developments of the tools, and applications that are made available to users for accessing strong-motion data.

Conference Paper↗
USGS2009

Providing public standardized data access function: Lessons learned from accessing USGS Landsat archive

The geospatial community is experiencing a shift from having data locally to sharing them over the Web. However, not all the data accessing systems are built in compliance with open geospatial standards and thus are weak in terms of interoperability. The USGS Landsat data are now available through free electronic access though not yet through standard Web service interfaces. This paper intends to discuss the experience and lessons learned from integrating a public data access function to the USGS Landsat data archive into a geospatial workflow environment. Currently available systems and their problems, proposed solutions and application scenarios are discussed.

Conference Paper↗
USGS1989

Statistical frequency analysis of flood records

The U.S. Geological Survey, like other Federal agencies, uses Hydrology Subcommittee Bulletin 17 for guidance in statistical frequency analysis of flood records. This paper describes the formal statistical and computational aspects of the Bulletin 17 methodology. The methodology includes provisions for dealing with high and low out-liers, historic peaks, and other anomalous flood data. If these options are inadequate, alternative procedures may be used if properly documented.

Conference Paper↗
USGS1994

San Francisco Bay test case for 3-D model verification

This paper describes a field test case for 3-D hydrodynamic model verification using data from Carquinez Strait in San Francisco Bay, California. It will be disseminated by the ASCE Computational Hydraulics task committee on 3-D Free-Surface Hydrodynamic Model Verifications during late 1994.

Conference Paper↗
USGS2015

Treatment of trace organic compounds in common onsite wastewater systems

Onsite wastewater systems (OWS) have historically been relied on to treat conventional pollutants and pathogens in a fashion similar to that expected from centralized wastewater systems. However, based on the occurrence of, and potential effects from, contaminants of emerging concern in wastewaters, OWS as well as centralized systems need to account for these compounds in system design and use. One group of contaminants involves organic compounds such as those associated with consumer product chemicals and pharmaceuticals, which are collectively referred to as trace organic compounds (TOrCs) due to their very low levels (e.g., ng/L to ug/L) relative to other pollutants. The question being confronted today is how best to account for TOrCs in onsite system design and use while also achieving other goals such as system simplicity, limited operation and maintenance requirements, low cost, and sustainability. In contrast to conventional pollutants such as nutrients and pathogens which have specific and achievable treatment goals, there are currently no enforceable treatment standards for TOrCs, which often have non-traditional toxicological endpoints (i.e. endocrine disruption). As highlighted in this paper, there are a large number of TOrCs that can be present in OWS and they have different properties, can be present at different frequencies of occurrence and concentrations, and have different susceptibilities to treatment in OWS. In general, based on the studies summarized in this paper, TOrCs normally should not require additional considerations beyond those for conventional pollutants and pathogens (e.g., nitrogen or bacteria and virus) during design and use of OWS. That said, there are situations where TOrCs could be a serious concern warranting special consideration in system design and use. In this paper, the frequency of occurrence of TOrCs and the range of concentrations encountered are highlighted. An evolving approach is outlined that could help assess the likelihood of occurrence and levels of TOrCs along with the treatment anticipated in different OWS and assimilation conditions.

Conference Paper↗
USGS2007

Consistency of L4 TM absolute calibration with respect to the L5 TM sensor based on near-simultaneous image acquisition

The Landsat archive provides more than 35 years of uninterrupted multispectral remotely sensed data of Earth observations. Since 1972, Landsat missions have carried different types of sensors, from the Return Beam Vidicon (RBV) camera to the Enhanced Thematic Mapper Plus (ETM+). However, the Thematic Mapper (TM) sensors on Landsat 4 (L4) and Landsat 5 (L5), launched in 1982 and 1984 respectively, are the backbone of an extensive archive. Effective April 2, 2007, the radiometric calibration of L5 TM data processed and distributed by the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) was updated to use an improved lifetime gain model, based on the instrument's detector response to pseudo-invariant desert site data and cross-calibration with the L7 ETM+. However, no modifications were ever made to the radiometric calibration procedure of the Landsat 4 (L4) TM data. The L4 TM radiometric calibration procedure has continued to use the Internal Calibrator (IC) based calibration algorithms and the post calibration dynamic ranges, as previously defined. To evaluate the "current" absolute accuracy of these two sensors, image pairs from the L5 TM and L4 TM sensors were compared. The number of coincident image pairs in the USGS EROS archive is limited, so the scene selection for the cross-calibration studies proved to be a challenge. Additionally, because of the lack of near-simultaneous images available over well-characterized and traditionally used calibration sites, alternate sites that have high reflectance, large dynamic range, high spatial uniformity, high sun elevation, and minimal cloud cover were investigated. The alternate sites were identified in Yuma, Iraq, Egypt, Libya, and Algeria. The cross-calibration approach involved comparing image statistics derived from large common areas observed eight days apart by the two sensors. This paper summarizes the average percent differences in reflectance estimates obtained between the two sensors. The work presented in this paper is a first step in understanding the current performance of L4 TM absolute calibration and potentially serves as a platform to revise and improve the radiometric calibration procedures implemented for the processing of L4 TM data.

Conference Paper↗
USGS1984

COORDINATION OF FEDERAL DIGITAL CARTOGRAPHIC ACTIVITIES.

Throughout the Federal Government, applications are emerging for spatial data bases that require digital cartographic data as a framework. This paper describes some major applications of spatial data in the Federal Government, and it discusses the extent to which these data needs are being coordinated. Efforts are outlined towards further coordination of digital cartographic data bases and production in the Federal Government.

Conference Paper↗
USGS1989

Criteria for a sediment data set

The transport of sediment through a hydrologic system or basin is an extremely complex phenomenon. Many factors affect this movement. Criteria are established for an 'ultimate' or complete sediment data set, and guidelines are given for the collection of alluvial data. The paper describes what parameters need to be measured and stored to obtain a complete sediment and hydraulic data set that could be used to compute sediment transport using any prominently known sediment-transport equation. The criteria address only the collection of data for noncohesive sediment.

Conference Paper↗
USGS2017

Wave dynamics and flooding on low-lying tropical reef-lined coasts

Many tropical islands and coasts are lined with coral reefs. These reefs are host to valuable ecosystems that support abundant marine species and provide resources for fisheries and recreation. As a flood defense, reefs protect coastlines from coastal storm damage and flooding by reducing the majority of incident wave energy. However, during storm and large swell conditions, coastal wave-driven flooding and overwash still occur due to high water levels, (infra) gravity waves, and/or low-frequency wave resonance. The wave and flooding effects cause erosion, damage to infrastructure, agricultural crops, and salinization of precious drinking water supplies. These impacts, which are likely to increase due to climate change and ongoing development on the islands, may cause many low-lying tropical islands and coastal areas to become uninhabitable before the end of the century. This paper investigates aspects of wave dynamics for the case of a small island in the tropical Pacific Ocean, shows projections of flooding under climate change scenarios, and outlines approaches to generalize the results to other islands, including mitigation options.

Conference Paper↗
USGS2022

Scaling-up deep learning predictions of hydrography from IfSAR data in Alaska

The United States National Hydrography Dataset (NHD) is a database of vector features representing the surface water features for the country. The NHD was originally compiled from hydrographic content on U.S. Geological Survey topographic maps but is being updated with higher quality feature representations through flow-routing techniques that derive hydrography from high-resolution elevation data. However, deriving hydrography through flow-routing methods is a complex process that needs to be tailored to different geographic conditions, which can lead to varying solutions. To address this problem, this paper evaluates automated deep learning and its transferability to extract hydrography from interferometric synthetic aperture radar (IfSAR) elevation data spanning a range of geographic conditions in Alaska.

Alaska↗