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At least 1,405 records · Page 78Linked to original sources

USGS1997

Stratigraphy and geophysical logs from a corehole drilled to bedrock at Robins Point, J-Field, Edgewood area, Aberdeen Proving Ground, Maryland

A continuous core was recovered from a 961-foot- deep stratigraphic corehole at Robins Point, located at the southeastern tip of the Gunpowder Neck Peninsula, Harford County, Maryland. A 2-inch- diameter ground-water-quality observation well was installed with the screen set at a depth of 392 to 402 feet (ft). Geophysical logs obtained from thecorehole include: natural gamma, multipoint normal resistivity (16-inch and 64-inch), 4-ft-guard focused resistivity, acoustic (sonic) velocity, and caliper. Pollen analysis of 34 samples provided relativestratigraphic ages. Lithologies encountered in ascending order (surface elevation 4 ft above mean sea level), include: 72.4 ft of weatheredmetamorphic rock and saprolie, 711.4 ft of lower and upper Cretaceous fluvio-deltaic deposits, and 145.9 ft of Pleistocene and 31.3 ft of Holocene(?) fluvial and estuarine deposits. Aquifers and confining units identified include, in descending order: 41.8 ft of surficial aquifer, 90.9 ft of upper paleochannel confining unit, 28.8 ft of paleochannel confined aquifer, 15.7 ft of lower paleochannel confining unit, 123.7 ft of Upper Patapsco aquifer, 44.6 ft of Upper Patapsco confining unit, 92.8 ft of Middle Patapsco aquifer, 57.3 ft of Lower Patapsco confining unit, 151.7 ft of Lower Patapsco aquifer, 115.4 ft of Potomac confining unit, 126.4 ft of Patuxent aquifer, an aquifer of 23.4 ft of saprolite, and 48.7 ft of weathered-rock/saprolite confining unit.

Open-File Report↗

USGS1998

Measured flow and tracer-dye data showing the anthropogenic effects on the hydrodynamics of south Sacramento-San Joaquin Delta, California, spring 1996 and 1997

Tidal flows were measured using acoustic Doppler current profilers and ultrasonic velocity meters during spring 1996 and 1997 in south Sacramento-San Joaquin Delta, California, when (1) a temporary barrier was installed at the head of Old River to prevent the entrance of migrating San Joaquin River salmon smolts, (2) the rate of water export from the south Delta was reduced for an extended period of time, and (3) a 30-day pulse flow was created on the San Joaquin River to move salmon smolts north away from the export facilities during spring 1997. Tracer-dye measurements also were made under these three conditions.

Open-File Report↗

USGS1999

Turbidite pathways in Cascadia Basin and Tufts abyssal plain, Part A, Astoria Channel, Blanco Valley, and Gorda Basin

This open-file report was prepared in support of the USGS Earthquake Hazards of Cascadia Project. The primary objective of this phase of the project is to determine recurrence intervals of turbidites in Cascadia basin-floor channel systems and evaluate implications of this event record for the paleoseismic history of the Cascadia subduction zone. The purpose of this study is to determine whether the canyon/channel systems themselves are blocked or deformed in such a way that the downstream turbidite stratigraphy might be biased. To accomplish this investigation approximately 7500 kilometers of pre-existing 3.5 KHz seismic data were evaluated to determine the direction and extent of the Astoria Channel/pathway system, which originates at the base of the Astoria Fan. Additionally, distribution and thickness of turbidite sediment sequences were determined along each identified pathway. Bathymetery and distance were used to determine gradients along the main pathway axis and for each of the secondary pathways that feed into it. Channel pathways were identified on the basis of channel phyisiography, where visible at the seafloor, subbottom channel configuration, and acoustic packets of sediments that might represent turbidite deposits. A principal result of this study is that the Astoria Channel/pathway extends continuously from the base of the Astoria Fan southward along the base of the continental slope through the Blanco Valley, then heads southwestward through the Gorda Basin and into the region of the Escanaba Trough. Additionally it was determined that the Astoria Channel is filled and basically buried for it's full length south of 44 degrees latitude. The 44 North Slump, as defined by Goldfinger (1999, see Map 3 ref.), may have been instrumental in blocking the pathway and thus contributed to the filling of the channel/pathway. Sheets 1 and 2 show the Astoria and secondary turbidite pathways highlighted in blue. Ship survey tracklines are shown for the area studied; they are time and date coded, and color keyed to each ship ID data base listed at the bottom of each sheet. The first letter in the cruise ID is an abbreviation letter for the ship name, the following numbers represent the consecutive cruise number of that year, followed by the year number. The letters at the end of the ID represent the survey area, ie. NC- northern California, NP- north Pacific. Locations of selected sample seismic sections illustrated on sheets 3-5 also are shown. Scales for each of the sheets are the same as for sheets 3-5, which allows for overlaying of track data onto the interpretations shown on Maps A-C. Sheets 3 (MAP A), 4 (MAP B), and 5 (MAP C) show channel pathway location, bathymetric depth based on the USGS COW data base (Ca/Or/Wa), pathway morphology, and thickness of turbidite sediment fill at various locations. The interpreted turbidite sediments are color highlighted on the selected seismic sections to differentiate them from the typical deep sea sediments below and to the side of the turbidite pathways. Thickness of sediment fill, in meters, is shown along major pathways in white circular highlights. The data and interpretations rest on a background of USGS GLORIA side scan sonar imagery (1984) to illustrate the relationship of pathway position to sub sea features. Channel distance points are plotted along channel centerlines at 20,000 m intervals. These points begin at the start of each interpreted channel pathway. A bathymetric depth was assigned to each distance point. These data points were then used to construct channel gradient curves for the Astoria, Eel, Bear Valley, and Mendocino channel pathways. These gradients are plotted on sheet 6 of this report and illustrate the similarities and differences between each of the pathways. Sheet 7 shows various views of the Mendocino/Mattole Canyon heads as an example of useful derivative information of the Seabeam bathymetric data. These views illustrate that the Mendocino pathway probably was directed from it's canyon mouth, to the northwest at an earlier time, but was diverted to the west along the base of the Mendocino Ridge by a major fault event in the recent past. Offset of the southwest channel wall is readily evident in views B and D. This apparent disruption complicates the turbidite history of the Mendocino pathway.

California;Oregon↗

USGS2000

Surveys of water velocities in the vicinity of the discharge-release gates of Salamonie Lake Dam, northeastern Indiana, spring and winter 1998

Two water-velocity surveys in the vicinity of the discharge-release gates were performed at the Salamonie Lake flood-control reservoir in northeastern Indiana during periods of high-discharge release. One survey was done in the spring when the reservoir pool was at high elevation; the other survey was in the winter when the reservoir pool was low. The maximum measured velocity was 2.4 feet per second for the spring survey and 1.9 feet per second for the winter survey. The maximum measured velocities occurred in the immediate vicinity of the spillway tower containing the discharge-release gates. Velocity-field magnitudes diminished rapidly with distance from the tower. Beyond an estimated 40 feet from the tower, velocity magnitudes were below 0.5 feet per second. For the spring and winter surveys, data were collected along four transects that were parallel to the face of the spillway tower. The transects were at the following approximate distances from the spillway tower: 900, 600, and 300 feet and as close to the tower as practical. For the spring and winter surveys, velocity-contour plots were produced for the transects closest to the tower. Plots were not made for the transects at 900-, 600-, and 300-foot intervals because velocities were negligible at these distances. An acoustic Doppler current profiler (ADCP) mounted on a boat was used to collect velocity and depth data and to compute positions of the velocity and depth data relative to the boat track. A global positioning system (GPS) was used to collect earth-referenced position data, and a GPS base station receiver was used to improve the accuracy of the earth-referenced position data. The earth-referenced position data were used to transform the ADCP-computed positions (which were relative to boat tracks) to positions referenced to a point on the spillway tower.

Indiana↗

USGS1999

Analysis of geophysical logs, at North Penn Area 6 Superfund Site, Lansdale, Montgomery County, Pennsylvania

The U.S. Geological Survey (USGS), as part of technical assistance to the U.S. Environmental Protection Agency (USEPA), collected borehole geophysical log data in 34 industrial, commercial, and public supply wells and 28 monitor wells at the North Penn Area 6 Superfund Site, in Lansdale, Pa., from August 22, 1995, through August 29, 1997. The wells range in depth from 50 to 1,027 feet below land surface and are drilled in Triassic-age shales and siltstones of the Brunswick Group and Lockatong Formation. The geophysical log data were collected to help describe the hydrogeologic framework in the area and to provide guidance in the reconstruction of the 28 monitor wells drilled during summer 1997. At the time of logging, all wells had open-hole construction. The geophysical logs, caliper, fluid-resistivity, and fluid-temperature, and borehole video logs were used to determine the vertical distribution of water-bearing fractures. Heatpulse-flowmeter measurements were used to determine vertical borehole flow under pumping and nonpumping conditions. The most productive fractures generally could be determined from heatpulse-flowmeter measurements under pumping conditions. Vertical borehole flow was measured under nonpumping conditions in most wells that had more than one water-bearing fracture. Upward flow was measured in 35 wells and probably is a result of natural head differences between fractures in the local ground-water-flow system. Downward flow was measured in 11 wells and commonly indicated differences in hydraulic heads of the fractures caused by nearby pumping. Both upward and downward flow was measured in three wells. No flow was detected in eight wells. Natural-gamma-ray logs were used to estimate the attitude of bedding. Thin shale marker beds, shown as spikes of elevated radioactivity in the natural-gamma logs of some wells throughout the area, enable the determination of bedding-plane orientation from three-point correlations. Generally, the marker beds in and near Lansdale strike about N. 48°-60° E. and dip about 11° NW. Acoustic televiewer logs run in selected boreholes indicate that the attitude of many water-bearing fractures commonly is similar to that of bedding.

Pennsylvania↗

USGS2008

Seismicity and infrasound associated with explosions at Mount St. Helens, 2004-2005

Six explosions occurred during 2004-5 in association with renewed eruptive activity at Mount St. Helens, Washington. Of four explosions in October 2004, none had precursory seismicity and two had explosion-related seismic tremor that marked the end of the explosion. However, seismicity levels dropped following each of the October explosions, providing the primary instrumental means for explosion detection during the initial vent-clearing phase. In contrast, explosions on January 16 and March 8, 2005, produced noticeable seismicity in the form of explosion-related tremor, infrasonic signals, and, in the case of the March 8 explosion, an increase in event size ~2 hours before the explosion. In both 2005 cases seismic tremor appeared before any infrasonic signals and was best recorded on stations located within the crater. These explosions demonstrated that reliable explosion detection at volcanoes like Mount St. Helens requires seismic stations within 1-2 km of the vent and stations with multiple acoustic sensors.

Washington↗

USGS2008

Views of the Sea Floor in Northern Monterey Bay, California

A sonar survey that produced unprecedented high-resolution images of the sea floor in northern Monterey Bay was conducted in 2005 and 2006. The survey, performed over 14 days by the U.S. Geological Survey (USGS), consisted of 172 tracklines and over 300 million soundings and covered an area of 12.2 km2 (4.7 mi2). The goals of this survey were to collect high-resolution bathymetry (depth to the sea floor) and acoustic backscatter data (amount of sound energy bounced back from the sea floor, which provides information on sea-floor hardness and texture) from the inner continental shelf. These data will provide a baseline for future change analyses, geologic mapping, sediment- and contaminant-transport studies, benthic-habitat delineation, and numerical modeling efforts. The survey shows that the inner shelf in this area is extremely varied in nature, encompassing flat sandy areas, faults, boulder fields, and complex bedrock ridges that support rich marine ecosystems. Furthermore, many of these complex bedrock ridges form the ?reefs? that result in a number of California?s classic surf breaks.

Scientific Investigations Map↗

USGS2011

Bathymetric and sediment facies maps for China Bend and Marcus Flats, Franklin D. Roosevelt Lake, Washington, 2008 and 2009

The U.S. Geological Survey (USGS) created bathymetric and sediment facies maps for portions of two reaches of Lake Roosevelt in support of an interdisciplinary study of white sturgeon (Acipenser transmontanus) and their habitat areas within Franklin D. Roosevelt Lake, Washington. In October 2008, scientists from the USGS used a boat-mounted multibeam echo sounder (MBES) to describe bathymetric data to characterize surface relief at China Bend and Marcus Flats, between Northport and Kettle Falls, Washington. In March 2009, an underwater video camera was used to view and record sediment facies that were then characterized by sediment type, grain size, and areas of sand deposition. Smelter slag has been identified as having the characteristics of sand-sized black particles; the two non-invasive surveys attempted to identify areas containing black-colored particulate matter that may be elements and minerals, organic material, or slag. The white sturgeon population in Lake Roosevelt is threatened by the failure of natural recruitment, resulting in a native population that consists primarily of aging fish and that is gradually declining as fish die and are not replaced by nonhatchery reared juvenile fish. These fish spawn and rear in the riverine and upper reservoir reaches where smelter slag is present in the sediment of the river lake bed. Effects of slag on the white sturgeon population in Lake Roosevelt are largely unknown. Two recent studies demonstrated that copper and other metals are mobilized from slag in aqueous environments with concentrations of copper and zinc in bed sediments reaching levels of 10,000 and 30,000 mg/kg due to the presence of smelter slag. Copper was found to be highly toxic to 30-day-old white sturgeon with 96-h LC50 concentrations ranging from 3 to 5 (u or mu)g copper per liter. Older juvenile and adult sturgeons commonly ingest substantial amounts of sediment while foraging. Future study efforts in Lake Roosevelt should include sampling of bottom material to confirm the presence or absence of slag material indicated on the map. In addition, follow-up acoustic work to determine stream velocities at varying discharges, in conjunction with sediment mapping, would be helpful to more accurately identify areas of scour and areas of sediment deposition where slag deposits may accumulate within the Marcus Flats and China Bend reaches. MBES mapping could also be used to determine changes in bed elevation and sedimentation in the study reaches and could help evaluate annual deposition and provide estimates on fine-sediment thickness.

Washington↗

USGS2012

California State Waters Map Series — Hueneme Canyon and vicinity, California

California↗

USGS2013

Bedrock topography of western Cape Cod, Massachusetts, based on bedrock altitudes from geologic borings and analysis of ambient seismic noise by the horizontal-to-vertical spectral-ratio method

This report presents a topographic map of the bedrock surface beneath western Cape Cod, Massachusetts, that was prepared for use in groundwater-flow models of the Sagamore lens of the Cape Cod aquifer. The bedrock surface of western Cape Cod had been characterized previously through seismic refraction surveys and borings drilled to bedrock. The borings were mostly on and near the Massachusetts Military Reservation (MMR). The bedrock surface was first mapped by Oldale (1969), and mapping was updated in 2006 by the Air Force Center for Environmental Excellence (AFCEE, 2006). This report updates the bedrock-surface map with new data points collected by using a passive seismic technique based on the horizontal-to-vertical spectral ratio (HVSR) of ambient seismic noise (Lane and others, 2008) and from borings drilled to bedrock since the 2006 map was prepared. The HVSR method is based on a relationship between the resonance frequency of ambient seismic noise as measured at land surface and the thickness of the unconsolidated sediments that overlie consolidated bedrock. The HVSR method was shown by Lane and others (2008) to be an effective method for determining sediment thickness on Cape Cod owing to the distinct difference in the acoustic impedance between the sediments and the underlying bedrock. The HVSR data for 164 sites were combined with data from 559 borings to bedrock in the study area to create a spatially distributed dataset that was manually contoured to prepare a topographic map of the bedrock surface. The interpreted bedrock surface generally slopes downward to the southeast as was shown on the earlier maps by Oldale (1969) and AFCEE (2006). The surface also has complex small-scale topography characteristic of a glacially eroded surface. More information about the methods used to prepare the map is given in the pamphlet that accompanies this plate.

Massachusetts↗

USGS2013

California State Waters Map Series — Offshore of Ventura, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Ventura map area lies within the Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges, and the region is presently undergoing north-south shortening. The city of Ventura is the major cultural center in the map area. The Ventura River cuts through Ventura, draining the Santa Ynez Mountains and the coastal hills north of Ventura. Northwest of Ventura, the coastal zone is a narrow strip containing highway and railway transportation corridors and a few small residential clusters. Rincon Island, an island constructed for oil and gas production, lies offshore of Punta Gorda. Southeast of Ventura, the coastal zone consists of the mouth and broad, alluvial plains of the Santa Clara River, and the region is characterized by urban and agricultural development. Ventura Harbor sits just north of the mouth of the Santa Clara River, in an area formerly occupied by lagoons and marshes. The Offshore of Ventura map area lies in the eastern part of the Santa Barbara littoral cell, whose littoral drift is to the east-southeast. Drift rates of about 700,000 to 1,150,000 tons/yr have been reported at Ventura Harbor. At the east end of the littoral cell, eastward-moving sediment is trapped by Hueneme and Mugu Canyons and then transported into the deep-water Santa Monica Basin. The largest sediment source to this littoral cell (and the largest in all of southern California) is the Santa Clara River, which has an estimated annual sediment flux of 3.1 million tons. In addition, the Ventura River yields about 270,000 tons of sediment annually. Despite the large local sediment supply, coastal erosion problems are ongoing in the map area. Riprap, revetments, and seawalls variably protect the coast within and north of Ventura. The offshore part of the map area mainly consists of relatively flat, shallow continental shelf, which dips so gently (about 0.2° to 0.4°) that water depths at the 3-nautical-mile limit of California’s State Waters are just 20 to 40 m. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north and west by Point Conception and the Channel Islands; long-period swells affecting the area are mainly from the south-southwest. Fair-weather wave base is typically shallower than 20-m water depth, but winter storms are capable of resuspending fine-grained sediments in 30 m of water, and so shelf sediments in the map area probably are remobilized on an annual basis. The shelf is underlain by tens of meters of interbedded upper Quaternary shelf, estuarine, and fluvial sediments deposited as sea level fluctuated up and down in the last several hundred thousand years. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft sediment and isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Ventura map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats lie within the Shelf (continental shelf) megahabitat, dominated by a flat seafloor and substrates formed from deposition of fluvial and marine sediment during sea-level rise. This flat, fairly homogeneous seafloor, composed primarily of unconsolidated sand and mud and local deposits of gravel, cobbles, and pebbles, provides promising habitat for groundfish, crabs, shrimp, and other marine benthic organisms. The only significant interruptions to this homogeneous habitat type are exposures of hard, irregular sedimentary bedrock and coarse-grained sediment where potential habitats for rockfish and related species exist.

California↗

USGS2013

California State Waters Map Series: Offshore of Carpinteria, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Carpinteria map area lies within the central Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and the region is presently undergoing north-south shortening. The small city of Carpinteria is the most significant onshore cultural center in the map area; the smaller town of Summerland lies west of Carpinteria. These communities rest on a relatively flat coastal piedmont that is surrounded on the north, east, and west by hilly relief on the flanks of the Santa Ynez Mountains. El Estero, a salt marsh on the coast west of Carpinteria, is an ecologically important coastal estuary. Southeast of Carpinteria, the coastal zone is narrow strip containing highway and railway transportation corridors and a few small residential clusters. Rincon Point is a well-known world-class surf break, and Rincon Island, constructed for oil and gas production, lies offshore of Punta Gorda. The steep bluffs backing the coastal strip are geologically unstable, and coastal erosion problems are ongoing in the map area; most notably, landslides in 2005 struck the small coastal community of La Conchita, engulfing houses and killing ten people. The Offshore of Carpinteria map area lies in the central part of the Santa Barbara littoral cell, whose littoral drift is to the east-southeast. Drift rates have been estimated to be about 400,000 tons/yr at Santa Barbara Harbor (about 15 km west of Carpinteria). At the east end of the littoral cell, eastward-moving sediment is trapped by Hueneme and Mugu Canyons and then transported to the deep-water Santa Monica Basin. Sediment supply to the western and central part of the littoral cell is largely from relatively small transverse coastal watersheds, which have an estimated cumulative annual sediment flux of 640,000 tons/yr. The much larger Ventura and Santa Clara Rivers, the mouths of which are about 25 to 30 km southeast of Carpinteria, yield an estimated 3.4 million tons of sediment annually, the coarser sediment load generally moving southeast, down the coast, and the finer sediment load moving both upcoast and offshore. The offshore part of the map area consists of a relatively flat and shallow continental shelf, which dips so gently (about 0.4° to 0.5°) that water depths at the 3-nautical-mile limit of California’s State Waters are 40 to 45 m. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north and northwest by Point Conception and from the south and southwest by offshore islands and banks. Fair-weather wave base is typically shallower than 20-m water depth, but winter storms are capable of resuspending fine-grained sediments in 30 m of water, and so shelf sediments in the map area probably are remobilized on an annual basis. The shelf is underlain by variable amounts of upper Quaternary shelf, estuarine, and fluvial sediments that thicken to the south. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft sediment and isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Carpinteria map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats lie within the Shelf (continental shelf) megahabitat, dominated by a flat seafloor and substrates formed from deposition of fluvial and marine sediment during sea-level rise. This fairly homogeneous seafloor provides promising habitat for groundfish, crabs, shrimp, and other marine benthic organisms. The only significant interruptions to this homogeneous habitat type are the exposures of hard, irregular, and hummocky sedimentary bedrock and coarse-grained sediment where potential habitats for rockfish and related species exist.

California↗

USGS2013

Bathymetry, morphology, and lakebed geologic characteristics of potential Kokanee salmon spawning habitat in Lake Pend Oreille, Bayview and Lakeview quadrangles, Idaho

Kokanee salmon (Oncorhynchus nerka) are a keystone species in Lake Pend Oreille in northern Idaho, historically supporting a high-yield recreational fishery and serving as the primary prey for the threatened native bull trout (Salvelinus confluentus) and the Gerrard-strain rainbow trout (Oncorhynchus mykiss). After 1965, the kokanee population rapidly declined and has remained at a low level of abundance. Lake Pend Oreille is one of the deepest lakes in the United States, the largest lake in Idaho, and home to the U.S. Navy Acoustic Research Detachment Base. The U.S. Geological Survey and Idaho Department of Fish and Game are mapping the bathymetry, morphology, and the lakebed geologic units and embeddedness of potential kokanee salmon spawning habitat in Lake Pend Oreille. Relations between lake morphology, lakebed geologic units, and substrate embeddedness are characterized for the shore zone, rise zone, and open water in bays and the main stem of the lake. This detailed knowledge of physical habitat along the shoreline of Lake Pend Oreille is necessary to better evaluate and develop kokanee recovery actions.

Idaho↗

USGS2013

California State Waters Map Series: Offshore of Santa Barbara, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Santa Barbara map area lies within the central Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and geodetic studies indicate that the region is presently undergoing north-south shortening. Uplift rates (as much as 2.2 mm/yr) that are based on studies of onland marine terraces provide further evidence of significant shortening. The city of Santa Barbara, the main coastal population center in the map area, is part of a contiguous urban area that extends from Carpinteria to Goleta. This urban area was developed on the coalescing alluvial surfaces, uplifted marine terraces, and low hills that lie south of the east-west-trending Santa Ynez Mountains. Several beaches line the actively utilized Santa Barbara coastal zone, including Arroyo Burro Beach Park, Leadbetter Beach, East Beach, and “Butterfly Beach.” There are ongoing coastal erosion problems associated with both development and natural processes; between 1933–1934 and 1998, cliff erosion in the map area occurred at rates of about 0.1 to 1 m/yr, the largest amount (63 m) occurring at Arroyo Burro in the western part of the map area. In addition, development of the Santa Barbara Harbor, which began in 1928, lead to shoaling west of the harbor as the initial breakwater trapped sand, as well as to coastal erosion east of the harbor. Since 1959, annual harbor dredging has mitigated at least some of the downcoast erosion problems. The Offshore of Santa Barbara map area lies in the central part of the Santa Barbara littoral cell, which is characterized by littoral drift to the east-southeast. Drift rates have been estimated to be about 400,000 tons/yr at Santa Barbara Harbor. Sediment supply to the western and central parts of the littoral cell, including the map area, is largely from relatively small transverse coastal watersheds. Within the map area, these coastal watersheds include (from east to west) San Ysidro Creek, Oak Creek, Montecito Creek, Sycamore Creek, Mission Creek, Arroyo Burro, and Atascadero Creek. The Ventura and Santa Clara Rivers, the mouths of which are about 40 to 50 km southeast of Santa Barbara, are much larger sediment sources. Still farther east, eastward-moving sediment in the littoral cell is trapped by Hueneme and Mugu Canyons and then transported to the deep-water Santa Monica Basin. The offshore part of the map area consists of a relatively flat and shallow continental shelf, which dips gently seaward (about 0.4° to 0.8°) so that water depths at the 3-nautical-mile limit of California’s State Waters are about 45 m in the east and about 75 m in the west. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north and northwest by Point Conception and from the south and southwest by offshore islands and banks. The shelf is underlain by variable amounts of upper Quaternary shelf, estuarine, and fluvial sediments deposited as sea level fluctuated in the late Pleistocene. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft sediment and isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Santa Barbara map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats, which lie within the Shelf (continental shelf) megahabitat, range from soft, unconsolidated sediment to hard sedimentary bedrock. This heterogeneous seafloor provides promising habitat for rockfish, groundfish, crabs, shrimp, and other marine benthic organisms.

California↗

USGS2014

California State Waters Map Series: Offshore of Coal Oil Point, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Coal Oil Point map area lies within the central Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and geodetic studies indicate that the region is presently undergoing north-south shortening. Uplift rates (as much as 2.0 mm/yr) that are based on studies of onland marine terraces provide further evidence of significant shortening. The cities of Goleta and Isla Vista, the main population centers in the map area, are in the western part of a contiguous urban area that extends eastward through Santa Barbara to Carpinteria. This urban area is on the south flank of the east-west-trending Santa Ynez Mountains, on coalescing alluvial fans and uplifted marine terraces underlain by folded and faulted Miocene bedrock. In the map area, the relatively low-relief, elevated coastal bajada narrows from about 2.5 km wide in the east to less than 500 m wide in the west. Several beaches line the actively utilized coastal zone, including Isla Vista County Park beach, Coal Oil Point Reserve, and Goleta Beach County Park. The beaches are subject to erosion each winter during storm-wave attack, and then they undergo gradual recovery or accretion during the more gentle wave climate of the late spring, summer, and fall months. The Offshore of Coal Oil Point map area lies in the central part of the Santa Barbara littoral cell, which is characterized by littoral drift to the east-southeast. Longshore drift rates have been reported to range from about 160,000 to 800,000 tons/yr, averaging 400,000 tons/yr. Sediment supply to the western and central parts of the littoral cell, including the map area, is largely from relatively small transverse coastal watersheds. Within the map area, these coastal watersheds include (from east to west) Las Llagas Canyon, Gato Canyon, Las Varas Canyon, Dos Pueblos Canyon, Eagle Canyon, Tecolote Canyon, Winchester Canyon, Ellwood Canyon, Glen Annie Canyon, and San Jose Creek. The Santa Ynez and Santa Maria Rivers, the mouths of which are about 100 to 140 km northwest of the map area, are not significant sediment sources because Point Conception and Point Arguello provide obstacles to downcoast sediment transport and also because much of their sediment load is trapped in dams. The Ventura and Santa Clara Rivers, the mouths of which are about 45 to 55 km southeast of the map area, are much larger sediment sources. Still farther east, eastward-moving sediment in the littoral cell is trapped by Hueneme and Mugu Canyons and then transported to the deep-water Santa Monica Basin. The offshore part of the map area consists of a relatively flat and shallow continental shelf, which dips gently seaward (about 0.8° to 1.0°) so that water depths at the shelf break, roughly coincident with the California’s State Waters limit, are about 90 m. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north and northwest by Point Conception and from the south and southwest by offshore islands and banks. The shelf is underlain by variable amounts of upper Quaternary marine and fluvial sediments deposited as sea level fluctuated in the late Pleistocene. The large (130 km2) Goleta landslide complex lies along the shelf break in the southern part of the map area. This compound slump complex may have been initiated more than 200,000 years ago, but it also includes three recent failures that may have been generated between 8,000 to 10,000 years ago. A local, 5- to 10-m-high tsunami may have been generated from these failure events. The map area has had a long history of hydrocarbon development, which began in 1928 with discovery of the Ellwood oil field. Subsequent discoveries in the offshore include South Ellwood offshore oil field, Coal Oil Point oil field, and Naples oil and gas field. Development of South Ellwood offshore field began in 1966 from platform “Holly,” the last platform to be installed in California’s State Waters. The area also is known for “the world’s most spectacular marine hydrocarbon seeps,” and large tar seeps are exposed on beaches east of the mouth of Goleta Slough. Offshore seeps adjacent to South Ellwood oil field release about 40 tons per day of methane and about 19 tons per day of ethane, propane, butane, and higher hydrocarbons. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft sediment and isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Coal Oil Point map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats, which lie primarily within the Shelf (continental shelf) but also partly within the Flank (basin flank or continental slope) megahabitats, range from soft, unconsolidated sediment to hard sedimentary bedrock. This heterogeneous seafloor provides promising habitat for rockfish, groundfish, crabs, shrimp, and other marine benthic organisms.

California↗

USGS2014

California State Waters Map Series — Offshore of San Gregorio, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California's State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of San Gregorio map area is located in northern California, on the Pacific coast of the San Francisco Peninsula about 50 kilometers south of the Golden Gate. The map area lies offshore of the Santa Cruz Mountains, part of the northwest-trending Coast Ranges that run roughly parallel to the San Andreas Fault Zone. The Santa Cruz Mountains lie between the San Andreas Fault Zone and the San Gregorio Fault system. The nearest significant onshore cultural centers in the map area are San Gregorio and Pescadero, both unincorporated communities with populations well under 1,000. Both communities are situated inland of state beaches that share their names. No harbor facilities are within the Offshore of San Gregorio map area. The hilly coastal area is virtually undeveloped grazing land for sheep and cattle. The coastal geomorphology is controlled by late Pleistocene and Holocene slip in the San Gregorio Fault system. A westward bend in the San Andreas Fault Zone, southeast of the map area, coupled with right-lateral movement along the San Gregorio Fault system have caused regional folding and uplift. The coastal area consists of high coastal bluffs and vertical sea cliffs. Coastal promontories in the northern and southern parts of the map area are the result of right-lateral motion on strands of the San Gregorio Fault system. In the south, headlands near Pescadero Point have been uplifted by motion along the west strand of the San Gregorio Fault (also called the Frijoles Fault), which separates rocks of the Pigeon Point Formation south of the fault from rocks of the Purisima Formation north of the fault. The regional uplift in this map area has caused relatively shallow water depths within California's State Waters and, thus, little accommodation space for sediment accumulation. Sediment is observed offshore in the central part of the map area, in the shelter of the headlands north of the east strand of the San Gregorio Fault (also called the Coastways Fault) around Miramontes Point (about 5 km north of the map area) and also on the outer half of the California's State Waters shelf in the south where depths exceed 40 m. Sediment in the outer shelf of California's State Waters is rippled, indicating some mobility. The Offshore of San Gregorio map area lies within the cold-temperate biogeographic zone that is called either the "Oregonian province" or the "northern California ecoregion." This biogeographic province is maintained by the long-term stability of the southward-flowing California Current, an eastern limb of the North Pacific subtropical gyre that flows from Oregon to Baja California. At its midpoint off central California, the California Current transports subarctic surface (0–500 m deep) waters southward, about 150 to 1,300 km from shore. Seasonal northwesterly winds that are, in part, responsible for the California Current, generate coastal upwelling. The south end of the Oregonian province is at Point Conception (about 350 km south of the map area), although its associated phylogeographic group of marine fauna may extend beyond to the area offshore of Los Angeles in southern California. The ocean off of central California has experienced a warming over the last 50 years that is driving an ecosystem shift away from the productive subarctic regime towards a depopulated subtropical environment. Seafloor habitats in the Offshore of San Gregorio map area, which lies within the Shelf (continental shelf) megahabitat, range from significant rocky outcrops that support kelp-forest communities nearshore to rocky-reef communities in deep water. Biological productivity resulting from coastal upwelling supports diverse populations of sea birds such as Sooty Shearwater, Western Gull, Common Murre, Cassin's Auklet, and many other less populous bird species. In addition, an observable recovery of Humpback and Blue Whales has occurred in the area; both species are dependent on coastal upwelling to provide nutrients. The large extent of exposed inner shelf bedrock supports large forests of "bull kelp," which is well adapted for high wave-energy environments. Common fish species found in the kelp beds and rocky reefs include lingcod and various species of rockfish and greenling.

California↗

USGS2015

California State Waters Map Series: Offshore of Refugio Beach, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Refugio Beach map lies within the western Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and geodetic studies indicate that the region is presently undergoing north-south shortening. Uplift rates (as much as 0.5 mm/yr) that are based on studies of onland marine terraces provide further evidence of significant shortening. The coastal zone of this map area lies at the steep flank of the Santa Ynez Mountains. The crest of the range, which lies about 8 km from the shoreline (north of the map area), has a maximum elevation of about 780 m. This area is largely open space, partly used for livestock grazing, with no significant towns or population centers. Highway 101 crosses the map area, adjacent to and within a few hundred meters of the shoreline. The most significant developments are the recreational state beaches at El Capitan Beach and Refugio Beach. The beaches are subject to erosion each winter during storm-wave attack, and then they undergo gradual recovery or accretion during the more gentle wave climate of the late spring, summer, and fall months. The Offshore of Refugio Beach map area lies in the west-central part of the Santa Barbara littoral cell, which is characterized by west-to-east transport of sediment from Point Arguello on the northwest to Hueneme and Mugu Canyons on the southeast. Longshore drift rates have been reported to range from about 160,000 to 800,000 tons/yr, averaging 400,000 tons/yr. Sediment supply to the western and central part of the littoral cell, including the map area, is mainly from relatively small coastal watersheds. Within the map area, these coastal watersheds include (from east to west) Cañada del Capitan, Tajiquas Creek, Arroyo Hondo, Cañada del Molino, and several unnamed canyons and creeks. The Santa Ynez and Santa Maria Rivers, the mouths of which are 80 to 120 km northwest of the map area, are not considered significant sediment sources because Point Conception and Point Arguello provide obstacles to downcoast sediment transport and also because much of their sediment load is trapped in dams. The Ventura and Santa Clara Rivers, the mouths of which are about 70 km to the southeast of the map area, are not sediment sources for the map area. The offshore part of the map area consists of relatively flat and shallow continental shelf, which dips gently seaward (about 0.8° to 1.0°) so that water depths at the shelf break, roughly coincident with the California’s State Waters limit, are about 80 to 100 m. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north and northwest by Point Conception and from the south and southwest by offshore islands and banks. The shelf is underlain by variable amounts of upper Quaternary marine and fluvial sediments deposited as sea level fluctuated in the late Pleistocene. In the map area, the shelf break is at depths of about 90 m and lies about 5.6 to 6.4 km offshore. Beyond the shelf break, the slope is steep (as much as about 7°) and unstable. Several submarine landslides, including the large (130 km 2 ) Goleta landslide complex, have been documented offshore of Goleta, a few kilometers east of the map area. This compound slump complex may have been initiated more than 200,000 year ago, but it also includes three recent failures that may have been generated 8,000 to 10,000 years ago. A local, 10-m-high tsunami may have been generated from these failure events. Small folds related to local faulting are superimposed on the homocline that makes up the south flank of the Santa Ynez Mountains. One of these superimposed anticlines hosts the Molino gas field, which was discovered in 1962 and subsequently developed through directional drilling from onshore wells. The Oligocene Sespe and Vaqueros Formations are the reservoirs in the Molino gas field, and the map area includes numerous seafloor hydrocarbon seeps. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft, unconsolidated sediment interspersed with isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Refugio Beach map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats, which lie primarily within the Shelf (continental shelf) but also partly within the Flank (basin flank or continental slope) megahabitats, primarily are composed of soft sediment interrupted by a few carbonate mounds. This homogeneous seafloor of sediment and low-relief bedrock provides promising habitat for groundfish, crabs, shrimp, and other marine benthic organisms.

California↗

USGS2022

Bathymetric contour maps, surface area and capacity tables, and bathymetric change maps for selected water-supply lakes in northwestern Missouri, 2019 and 2020

Bathymetric data were collected at 12 water-supply lakes in northwestern Missouri by the U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources and in collaboration with various local agencies, as part of a multiyear effort to establish or update the surface area and capacity tables for the surveyed lakes. Ten of the lakes were surveyed from July to September 2019, one of the original 10 was resurveyed in March 2020, and two lakes of high interest near Maryville were surveyed in June 2020. Six of the lakes had been surveyed by the U.S. Geological Survey before, and the recent surveys were compared to the earlier surveys to document the changes in the bathymetric surface and capacity of the lake and to produce a bathymetric change map. Bathymetric data were collected using a high-resolution multibeam mapping system mounted on a boat. Supplemental depth data were collected in shallow areas with an acoustic Doppler current profiler on a remote-controlled boat. At Hamilton Reservoir, a Global Navigation Satellite System survey receiver was used to collect additional bathymetric data at several points across four transects and around the perimeter of a substantial shallow area filled with aquatic vegetation upstream from a low-clearance bridge on the northern arm. Data points from the various sources were exported at a gridded data resolution appropriate to each lake. Data outside the multibeam echosounder survey extent and greater than the surveyed water-surface elevation generally were obtained from data collected using aerial light detection and ranging point cloud data, 1/9 arc-second National Elevation Dataset data based on aerial light detection and ranging data, or both. A linear enforcement technique was used to add points to the dataset in areas of sparse data (the upper ends of coves where the water was shallow or aquatic vegetation precluded data acquisition) based on surrounding multibeam and upland data values. The various point datasets were used to produce a three-dimensional triangulated irregular network surface of the lake-bottom elevations for each lake. A surface area and capacity table was produced from the three-dimensional surface showing surface area and capacity at specified lake water-surface elevations. Various quality-assurance tests were conducted to ensure quality data were collected with the multibeam, including beam angle checks and patch tests. Additional quality-assurance tests were conducted on the gridded bathymetric data from the survey, the bathymetric surface created from the gridded data, and the contours created from the bathymetric survey. If data from a previous bathymetric survey existed at a given lake, a bathymetric change map was generated from the elevation difference between the previous survey and the 2019 bathymetric survey data points. After applying any vertical elevation changes to the previous survey data to ensure a match to the 2019 survey datum, coincident points between the surveys were found, and a bathymetric change map was generated using the coincident point data. A decrease in capacity was observed at all the lakes for which a previous survey existed. The decrease in capacity at the primary spillway or intake elevation ranged from 0.8 percent at Lake Viking to 21.4 percent at Middle Fork Grand River Reservoir. The mean bathymetric change ranged from 0.33 foot at Willow Brook Lake to 1.18 feet at Middle Fork Grand River Reservoir. The computed sedimentation rate generally ranged from 0.54 to 4.19 acre-feet per year at Maysville Lake and Middle Fork Grand River Reservoir, respectively; however, Lake Viking had the largest sedimentation rate of 14.9 acre-feet per year, despite having the smallest decrease in capacity at the spillway elevation of only 0.8 percent and a mean bathymetric change of only 0.4 foot. Evidence of dredging was observed in the bathymetric surface for Lake Viking. Some changes observed in some bathymetric change maps are hypothesized to result from the difference in data collection equipment and techniques between the previous and present bathymetric surveys. Certain erosional features around the perimeter of certain lakes may be the result of wave action during low-water years.

Missouri↗