SEARCH · Search USGS

Results for “Mississippi Geology”

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

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 865 records · Page 48Linked to original sources

USGS2017

Discriminating between natural vs induced seismicity from long-term deformation history of intraplate faults

To assess whether recent seismicity is induced by human activity or is of natural origin, we analyze fault displacements on high-resolution seismic reflection profiles for two regions in the central United States (CUS): the Fort Worth Basin (FWB) of Texas, and the northern Mississippi embayment (NME). Since 2009 earthquake activity in the CUS has increased dramatically, and numerous publications suggest that this increase is primarily due to induced earthquakes caused by deep-well injection of wastewater, both flowback water from hydrofracturing operations and produced water accompanying hydrocarbon production. Alternatively, some argue that these earthquakes are natural, and that the seismicity increase is a normal variation that occurs over millions of years. Our analysis shows that within the NME, faults deform both Quaternary alluvium and underlying sediments dating from Paleozoic through Tertiary, with displacement increasing with geologic unit age, documenting a long history of natural activity. In the FWB, a region of ongoing wastewater injection, basement faults show deformation of the Proterozoic and Paleozoic units, but little or no deformation of younger strata. Specifically, vertical displacements in the post-Pennsylvanian formations, if any, are below the resolution (~15 m) of the seismic data, far less than expected had these faults accumulated deformation over millions of years. Our results support the assertion that recent FWB earthquakes are of induced origin; this conclusion is entirely independent of analyses correlating seismicity and wastewater injection practices. To our knowledge this is the first study to discriminate natural and induced seismicity using classical structural geology analysis techniques.

Arkansas, Illinois, Mississippi, Missouri, Tenness↗

USGS2008

Geometry of the neoproterozoic and paleozoic rift margin of western Laurentia: Implications for mineral deposit settings

The U.S. and Canadian Cordilleran miogeocline evolved during several phases of Cryogenian-Devonian intracontinental rifting that formed the western mangin of Laurentia. Recent field and dating studies across central Idaho and northern Nevada result in identification of two segments of the rift margin. Resulting interpretations of rift geometry in the northern U.S. Cordillera are compatible with interpretations of northwest- striking asymmetric extensional segments subdivided by northeast-striking transform and transfer segments. The new interpretation permits integration of miogeoclinal segments along the length of the western North American Cordillera. For the U.S. Cordillera, miogeoclinal segments include the St. Mary-Moyie transform, eastern Washington- eastern Idaho upper-plate margin, Snake River transfer, Nevada-Utah lower-plate margin, and Mina transfer. The rift is orthogonal to most older basement domains, but the location of the transform-transfer zones suggests control of them by basement domain boundaries. The zigzag geometry of reentrants and promontories along the rift is paralleled by salients and recesses in younger thrust belts and by segmentation of younger extensional domains. Likewise, transform transfer zones localized subsequent transcurrent structures and igneous activity. Sediment-hosted mineral deposits trace the same zigzag geometry along the margin. Sedimentary exhalative (sedex) Zn-Pb-Ag ??Au and barite mineral deposits formed in continental-slope rocks during the Late Devonian-Mississippian and to a lesser degree, during the Cambrian-Early Ordovician. Such deposits formed during episodes of renewed extension along miogeoclinal segments. Carbonate-hosted Mississippi Valley- type (MVT) Zn-Pb deposits formed in structurally reactivated continental shelf rocks during the Late Devonian-Mississippian and Mesozoic due to reactivation of preexisting structures. The distribution and abundance of sedex and MVT deposits are controlled by the polarity and kinematics of the rift segment. Locally, discrete mineral belts parallel secondary structures such as rotated crustal blocks at depth that produced sedimentary subbasins and conduits for hydrothermal fluids. Where the miogeocline was overprinted by Mesozoic and Cenozoic deformation and magmatism, igneous rock-related mineral deposits are common. ??2008 Geological Society of America.

Geosphere↗

USGS2008

Vegetation Types in Coastal Louisiana in 2007

During the summer and fall of 2007, the U.S. Geological Survey, the Louisiana State University Agricultural Center, and the Louisiana Department of Wildlife and Fisheries Fur and Refuge Division jointly completed an aerial survey to collect data on 2007 vegetation types in coastal Louisiana. The current map presents the data collected in this effort. The 2007 aerial survey was conducted by using techniques developed over the last thirty years while conducting similar vegetation surveys. Transects flown were oriented in a north-south direction and spaced 1.87 mi (3 km) apart and covered coastal marshes from the Texas State line to the Mississippi State line and from the northern extent of fresh marshes to the southern end of saline (saltwater) marshes on the beaches of the Gulf of Mexico or of coastal bays. Navigation along these transects and to each sampling site was accomplished by using Global Positioning System (GPS) technology and geographic information system (GIS) software. As the surveyors reached each sampling station, observed areas of marsh were assigned as fresh, intermediate, brackish, or saline (saltwater) types, and dominant plant species were listed and ranked according to abundance. Delineations of marsh boundaries usually followed natural levees, bayous, or other features that impede or restrict water flow.

Louisiana↗

USGS1991

Fluid inclusion gas chemistry as a potential minerals exploration tool: Case studies from Creede, CO, Jerritt Canyon, NV, Coeur d'Alene district, ID and MT, southern Alaska mesothermal veins, and mid-continent MVT's

Recent advances in instrumentation now permit quantitative analysis of gas species from individual fluid inclusions. Fluid inclusion gas data can be applied to minerals exploration empirically to establish chemical (gas composition) signatures of the ore fluids, and conceptually through the development of genetic models of ore formation from a framework of integrated geologic, geochemical, and isotopic investigations. Case studies of fluid inclusion gas chemistry from ore deposits representing a spectrum of ore-forming processes and environments are presented to illustrate both the empirical and conceptual approaches. We consider epithermal silver-gold deposits of Creede, Colorado, Carlin-type sediment-hosted disseminated gold deposits of Jerritt Canyon, Nevada, metamorphic silver-base-metal veins of the Coeur d'Alene district, Idaho and Montana, gold-quartz veins in accreted terranes of southern Alaska, and the mid-continent base-metal sulfide deposits of Mississippi Valley-Type (MVT's). Variations in gas chemistry determine the redox state of the ore fluids, provide compositional input for gas geothermometers, characterize ore fluid chemistry (e.g., CH 4 CO 2 , H 2 SSO 2 , CO 2 /H 2 S, organic-rich fluids, gas-rich and gas-poor fluids), identify magmatic, meteoric, metamorphic, shallow and deep basin fluids in ore systems, locate upwelling plumes of magmatic-derived volatiles, zones of boiling and volatile separation, interfaces between contrasting fluids, and important zones of fluid mixing. Present techniques are immediately applicable to exploration programsas empirical studies that monitor fluid inclusion gas threshold concentration levels, presence or absence of certain gases, or changes in gas ratios. We suggest that the greater contribution of fluid inclusion gas analysis is in the integrated and comprehensive chemical dimension that gas data impart to genetic models, and in the exploration concepts based on processes and environments of ore formation derived from these genetic models.

Journal of Geochemical Exploration↗

USGS1984

U-Th-Pb isotope chronology of sulfide ores and rocks in the early Proterozoic metavolcanic belt of northern Wisconsin

Lead was probably derived from 3.7-b.y.-old source material about 1.8 to 1.9 b.y. ago. Data on metavolcanic and granitic rocks from the belt show that the U-Th-Pb systems in most were reset about 1.6 b.y. ago; a time of shearing and retrogressive metamorphism. A concordia plot of the whole-rock lead data shows that many of the rocks lost lead relative to uranium and thorium during the interval 200 to 400 m.y. ago. Similar ores might be sought between the northern Wisconsin metavolcanic belt and the Upper Mississippi Valley because the lead lost from the basement there might be available for ore formation in overlying units. The lead in the early Proterozoic metavolcanic belt of northern Wisconsin seems to have been derived from the same mantle parent as the late Archean metavolcanic belts of northeastern Minnesota and southern Ontario.

Economic Geology↗

USGS1994

Neogene and Quaternary foraminifera and paleoenvironments of a corehole from Horn Island, Mississippi

The only semipermanent surface water available on the Southern High Plains plateau of Texas and New Mexico is contained in saline lakes and in the playa lakes that form in shallow depressions, called playa basins, following heavy rainfall. The playas generally are accepted as the main source of recharge to the underlying High Plains (Ogallala) aquifer of the region, and they constitute the major wildlife habitat on the Southern High Plains. Their use as water sources, holding ponds, and waste-disposal sites by agricultural and industrial operations may potentially lead to ground-water contamination and habitat degradation. Therefore, playa lakes will play an essential role in the collection of surface-water quality and ecological data for the Southern High Plains study unit of the National Water-Quality Assessment program of the U.S. Geological Survey.

Open-File Report↗

USGS2026

The saline groundwater legacy of a large buried coastal paleo-estuary

Elevated groundwater salinity in coastal regions threatens the beneficial use of fresh groundwater. Coastal groundwater management typically focuses on preventing intrusion from modern sources of seawater; however, past geological processes can also leave a legacy of saline groundwater now hidden in the subsurface. Here, multiple extensive airborne electromagnetic surveys provide detailed evidence of residual salinity from a paleo-estuary filling a late Pleistocene incised valley impacting more than 10,000 km 2 that is now hidden beneath coastal Louisiana’s deltaic plain. Our results show that the three-dimensional pattern of saline groundwater beneath Louisiana mimics that of near-surface aquifers surrounding the modern Delaware Bay estuary, fingerprinting the signature of the past drowning of a large, incised valley of the Mississippi River following post-glacial sea-level rise. These findings demonstrate a new framework for understanding legacy sources of saltwater critical for managing stressed water resources along global coastlines.

Louisiana↗

USGS1993

Do ages of authigenic K-feldspar date the formation of Mississippi valley-type Pb-Zn deposits, central and southeastern United States?: Pb isotopic evidence

Pb concentrations and isotopic compositions have been determined for authigenic over-growths and detrital cores of K-feldspar from Cambrian sedimentary rocks in Texas, Tennessee, and Pennsylvania (referred to as group 1) and southeastern Missouri (referred to as group 2). Overgrowths and cores were separated by abrasion and analyzed separately. In three group 1 samples, cores have Pb isotopic ratios similar to initial ratios in K-feldspar from nearby Middle Proterozoic basement rocks ( 206 Pb/ 204 Pb =16.7-17.0). Pb ratios in overgrowths are radiogenic ( 206 Pb/ 204 Pb up to 19.3) and mostly are distinct from those in ore deposits in the southern Appalachians. Pb isotopic data for two samples of K-feldspar from southeastern Missouri are scattered; in one sample, cores and overgrowths contain radiogenic Pb, suggesting at least two periods of authigenic replacement, in agreement with petrographic evidence. Proterozoic material must still be present because 40 Ar/ 39 Ar stepwise analysis of a total (cores plus overgrowths) sample yields incremental ages ranging from about 500 to 750 Ma. The disparity in Pb isotopic ratios of group 1 overgrowths and Pb in nearby Mississippi Valley-type deposits implies that the regional authigenic K-feldspar event was not synchronous with ore deposition in the southeastern United States. In contrast, Pb isotopic ratios from group 2 authigenic K-feldspar are similar to ratios in ores of southeastern Missouri, suggesting a genetic relation in late Paleozoic time.

Geology↗

USGS2020

Council Monitoring and Assessment Program (CMAP): User guide for the Gulf Coast Monitoring and Assessment Portal

The Resources and Ecosystems Sustainability, Tourist Opportunities, and Revived Economies of the Gulf Coast States Act (RESTORE Act Final Rule at 31 C.F.R. Part 34) was signed into law on July 6, 2012. The RESTORE Act calls for a regional approach to restoring the long-term health of the valuable natural ecosystem and economy of the Gulf Coast region. The RESTORE Act dedicates 80 percent of civil and administrative penalties paid under the Clean Water Act, after the date of enactment, by the responsible parties in connection with the Deepwater Horizon oil spill to the Gulf Coast Restoration Trust Fund (Trust Fund) for ecosystem restoration, economic recovery, and tourism promotion in the Gulf Coast region. In addition to creating the Trust Fund, the RESTORE Act established the Gulf Coast Ecosystem Restoration Council (RESTORE Council or Council). The Council includes the Governors of the states of Alabama, Florida, Louisiana, Mississippi and Texas, the Secretaries of the U.S. Departments of Agriculture, the Army, Commerce, Homeland Security, and the Interior, and the Administrator of the U.S. Environmental Protection Agency. The Council plays a key role in developing strategies and implementing projects that help ensure the Gulf of Mexico’s natural resources are sustainable and available for future generations. The Council Monitoring and Assessment Program (CMAP) was approved as a Gulf-wide investment by the Council in the 2015 Initial Funded Priorities List and is administered jointly by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS). Funded activities include the organization of basic, foundational components for a Gulf-wide monitoring network to measure the efficacy of investments in Gulf restoration by the Council. The program, in coordination with the Gulf of Mexico Alliance (GOMA) and through collaboration with the Gulf States, federal and local partners, academia, non-governmental organizations, and business and industry, has leveraged existing resources, capacities, and expertise and built on existing monitoring programs and their data.

Alabama, Florida, Georgia, Louisiana, Mississippi,↗

USGS1997

Seismic evidence of Quaternary faulting in the Benton Hills area, southeast Missouri

Two reflection seismic profiles at English Hill, across the southern edge of the Benton Hills escarpment, southeast Missouri, establish that geologic structures at English Hill are of tectonic origin. The lowland area to the south of the escarpment is relatively undisturbed. The geology at English Hill is structurally complex, and reflection seismic and geologic data indicate extensive and episodic faulting of Paleozoic, Cretaceous, Tertiary, and Quaternary strata. The individual faults have near-vertical fault surfaces with maximum vertical separations on the order of 15 m. They appear to be clustered in north-northeast trending zones that essentially parallel one of the dominant Benton Hills structural trends. These observations suggest that previously mapped Quaternary faults at English Hill are deep-seated and tectonic in origin. This paper documents recent faulting at English Hill and is the first time late Quaternary, surface-rupture faulting has been recognized in the middle Mississippi River Valley region outside of the New Madrid seismic zone. This has important implications for earthquake assessment in the midcontinent.

Missouri↗

USGS2014

Topographic lidar survey of the Chandeleur Islands, Louisiana, February 6, 2012

This Data Series Report contains lidar elevation data collected February 6, 2012, for Chandeleur Islands, Louisiana. Point cloud data in lidar data exchange format (LAS) and bare earth digital elevation models (DEMs) in ERDAS Imagine raster format (IMG) are available as downloadable files. The point cloud data—data points described in three dimensions—were processed to extract bare earth data; therefore, the point cloud data are organized into the following classes: 1– and 17–unclassified, 2–ground, 9–water, and 10–breakline proximity. Digital Aerial Solutions, LLC, (DAS) was contracted by the U.S. Geological Survey (USGS) to collect and process these data. The lidar data were acquired at a horizontal spacing (or nominal pulse spacing) of 0.5 meters (m) or less. The USGS conducted two ground surveys in small areas on the Chandeleur Islands on February 5, 2012. DAS calculated a root mean square error (RMSEz) of 0.034 m by comparing the USGS ground survey point data to triangulated irregular network (TIN) models built from the lidar elevation data. This lidar survey was conducted to document the topography and topographic change of the Chandeleur Islands. The survey supports detailed studies of Louisiana, Mississippi and Alabama barrier islands that resolve annual and episodic changes in beaches, berms and dunes associated with processes driven by storms, sea-level rise, and even human restoration activities. These lidar data are available to Federal, State and local governments, emergency-response officials, resource managers, and the general public.

Louisiana↗

USGS2017

Five hydrologic and landscape databases for selected National Wildlife Refuges in the Southeastern United States

This report serves as metadata and a user guide for five out of six hydrologic and landscape databases developed by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, to describe data-collection, data-reduction, and data-analysis methods used to construct the databases and provides statistical and graphical descriptions of the databases. Six hydrologic and landscape databases were developed: (1) the Cache River and White River National Wildlife Refuges (NWRs) and contributing watersheds in Arkansas, Missouri, and Oklahoma, (2) the Cahaba River NWR and contributing watersheds in Alabama, (3) the Caloosahatchee and J.N. “Ding” Darling NWRs and contributing watersheds in Florida, (4) the Clarks River NWR and contributing watersheds in Kentucky, Tennessee, and Mississippi, (5) the Lower Suwannee NWR and contributing watersheds in Georgia and Florida, and (6) the Okefenokee NWR and contributing watersheds in Georgia and Florida. Each database is composed of a set of ASCII files, Microsoft Access files, and Microsoft Excel files. The databases were developed as an assessment and evaluation tool for use in examining NWR-specific hydrologic patterns and trends as related to water availability and water quality for NWR ecosystems, habitats, and target species. The databases include hydrologic time-series data, summary statistics on landscape and hydrologic time-series data, and hydroecological metrics that can be used to assess NWR hydrologic conditions and the availability of aquatic and riparian habitat. Landscape data that describe the NWR physiographic setting and the locations of hydrologic data-collection stations were compiled and mapped. Categories of landscape data include land cover, soil hydrologic characteristics, physiographic features, geographic and hydrographic boundaries, hydrographic features, and regional runoff estimates. The geographic extent of each database covers an area within which human activities, climatic variation, and hydrologic processes can potentially affect the hydrologic regime of the NWRs and adjacent areas. The hydrologic and landscape database for the Cache and White River NWRs and contributing watersheds in Arkansas, Missouri, and Oklahoma has been described and documented in detail (Buell and others, 2012). This report serves as a companion to the Buell and others (2012) report to describe and document the five subsequent hydrologic and landscape databases that were developed: Chapter A—the Cahaba River NWR and contributing watersheds in Alabama, Chapter B—the Caloosahatchee and J.N. “Ding” Darling NWRs and contributing watersheds in Florida, Chapter C—the Clarks River NWR and contributing watersheds in Kentucky, Tennessee, and Mississippi, Chapter D—the Lower Suwannee NWR and contributing watersheds in Georgia and Florida, and Chapter E—the Okefenokee NWR and contributing watersheds in Georgia and Florida.

Alabama, Arkansas, Florida, Georgia, Kentucky, Mis↗

USGS2008

Geologic framework of the 2005 Keathley Canyon gas hydrate research well, northern Gulf of Mexico

The Keathley Canyon sites drilled in 2005 by the Chevron Joint Industry Project are located along the southeastern edge of an intraslope minibasin (Casey basin) in the northern Gulf of Mexico at 1335 m water depth. Around the drill sites, a grid of 2D high-resolution multichannel seismic data designed to image depths down to at least 1000 m sub-bottom reveals 7 unconformities and disconformities that, with the seafloor, bound 7 identifiable seismic stratigraphic units. A major disconformity in the middle of the units stands out for its angular baselapping geometry. From these data, three episodes of sedimentary deposition and deformation are inferred. The oldest episode consists of fine-grained muds deposited during a period of relative stability in the basin (units e, f, and g). Both the BSR and inferred gas hydrate occur within these older units. The gas hydrate occurs in near-vertical fractures. A second episode (units c and d) involved large vertical displacements associated with infilling and ponding of sediment. This second interval corresponds to deposition of intercalated fine and coarse-grained material that was recovered in the drill hole that penetrated the thin edges of the regionally much thicker units. The final episode of deposition (units a and b) occurred during more subdued vertical motions. Hemipelagic drape (unit a) characterizes the modern seafloor. The present-day Casey basin is mostly filled. Its sill is part of a subsiding graben structure that is only 10-20 m shallower than the deepest point in the basin, indicating that gravity-driven transport would mostly bypass the basin. Contemporary faulting along the basin margins has selectively reactivated an older group of faults. The intercalated sand and mud deposits of units c and d are tentatively correlated with Late Pleistocene deposition derived from the western shelf-edge delta/depocenter of the Mississippi River, which was probably most active from 320 ka to 70 ka [Winker, C.D., Booth, J., 2000. Sedimentary dynamics of the salt-dominated continental slope, Gulf of Mexico: integration of observations from the seafloor, near-surface, and deep subsurface. In: Proceedings of the GCSSEPM Foundation 20th Annual Research Conference, Deep-water Reservoirs of the World, pp. 1059-1086]. The presence of sand within the gas hydrate stability zone (in units c and d) is not sufficient to concentrate gas hydrate even though dispersed gas hydrate occurs deeper in the fractured mud/clay-rich sections of units e and f.

Gulf of Mexico↗

USGS2001

Preface; Water quality of large U.S. rivers; results from the U.S. Geological Survey's National Stream Quality Accounting Network

The mission of the US Geological Survey (USGS) is to assess the quantity and quality of the earth resources of the USA and to provide information that will assist resource managers and policymakers at federal, state and local levels in making sound decisions. Characterizing the water quality of the largest rivers of the USA is a daunting prospect, especially given the resources available for the task. The most effective approach is uncertain and is legitimately a research topic. The National Stream Quality Accounting Network (NASQAN) was redesigned in 1995 to estimate the annual mass flux of constituents at a network of fixed stations in the Mississippi, Rio Grande, Colorado, and Columbia River basins. This special volume of Hydrological Processes contains a series of papers evaluating the data collected by NASQAN during its first 3 years of operation under this design. The NASQAN network complements other USGS national programs that are designed to address water quality at different scales. The National Water-Quality Assessment Program (Hirsch et al., 1988) is designed around river basins of 10 000 to 100 000 km2 (versus these NASQAN basins, which are 650 000 to 3 100 000 km2 at their most downstream stations). The USGS also operates the Hydrologic Benchmark Network that is focused on relatively pristine basins of only 10 to 100 km2 (Mast and Turk, 1999a,b; Clark et al., 2000; Mast et al., 2000).

Hydrological Processes↗

USGS1984

Planning report for the Gulf Coast Regional Aquifer-System Analysis in the Gulf of Mexico coastal plain, United States

Large quantities of water for municipal, industrial and agriculture use are supplied from the aquifers in Tertiary and younger sediments over an area of about 225,000 square miles in the Coastal Plain of Alabama, Arkansas, Florida, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Tennessee, and Texas. Three regional aquifer systems, the Mississippi Embayment aquifer system, the Coastal Lowlands aquifer system, and the Texas Coastal Uplands aquifer system have been developed to varying degrees throughout the area. A variety of problems has resulted from development such as movement of the saline-freshwater interface into parts of aquifers that were previously fresh, lowering of the potentiometric surface with resulting increases in pumping lift, and land-surface subsidence due to the compaction of clays within the aquifer. Increased demand for ground water is anticipated to meet the needs of urban growth, expanded energy development, and growth of irrigated agriculture. The U. S. Geological Survey initiated an eightyear study in 1981 to define the geohydrologic framework, describe the chemistry of the ground water, and to analyze the regional ground-water flow patterns. The objectives, plan, and organization of the study are described in this report and the major tasks to be undertaken are outlined.

Water-Resources Investigations Report↗

USGS1985

Barrier island arcs along abandoned Mississippi River deltas

Generation of transgressive barrier island arcs along the Mississippi River delta plain and preservation of barrier shoreline facies in their retreat paths on the inner shelf is controlled by: (1) shoreface translation; (2) age of the transgression; and (3) the thickness of the barrier island arc sediment package. Barrier island arcs experience an average relative sea level rise of 0.50–1.00 cm yr −1 and shoreface retreat rates range from 5–15 m yr −1 . Young barrier island arc sediment packages (Isles Dernieres) are thin and have experienced limited landward retreat of the shoreface. Older barrier island arcs (Chandeleur Islands) are thicker and have experienced significant landward movement of the shoreface because of the greater time available for retreat. If the transgressed barrier shoreline sediment package lies above the advancing ravinement surface, the entire sequence is truncated. A thin reworked sand sheet marks the shoreface retreat path. The base of the transgressive sediment package can lie below the ravinement surface in older barrier shorelines. In this setting, the superstructure of the barrier shoreline is truncated, leaving the basal portion of the transgressive sequence preserved on the inner shelf. A variety of transgressive stratigraphic sequences from sand sheets to truncated barrier islands to sand-filled tidal inlet scars have been identified by high resolution seismic profiling across the shoreface retreat paths of Mississippi delta barrier island arcs. One of these examples, the Isles Dernieres, represents a recently detached barrier island arc in the early stages of transgression. An older example, the Chandeleur Islands, represents a barrier island arc experiencing long-term shoreface retreat. This paper describes the stratigraphic character and preserved transgressive facies for the Isles Dernieres and Chandeleur Islands.

Marine Geology↗

USGS2013

Hurricane Isaac: observations and analysis of coastal change

Understanding storm-induced coastal change and forecasting these changes require knowledge of the physical processes associated with a storm and the geomorphology of the impacted coastline. The primary physical process of interest is sediment transport that is driven by waves, currents, and storm surge associated with storms. Storm surge, which is the rise in water level due to the wind, barometric pressure, and other factors, allows both waves and currents to impact parts of the coast not normally exposed to these processes. Coastal geomorphology reflects the coastal changes associated with extreme-storm processes. Relevant geomorphic variables that are observable before and after storms include sand dune elevation, beach width, shoreline position, sediment grain size, and foreshore beach slope. These variables, in addition to hydrodynamic processes, can be used to quantify coastal change and are used to predict coastal vulnerability to storms (Stockdon and others, 2007). The U.S. Geological Survey (USGS) National Assessment of Coastal Change Hazards (NACCH) project ( http://coastal.er.usgs.gov/national-assessment/ ) provides hazard information to those concerned about the Nation’s coastlines, including residents of coastal areas, government agencies responsible for coastal management, and coastal researchers. Extreme-storm research is a component of the NACCH project ( http://coastal.er.usgs.gov/hurricanes/ ) that includes development of predictive understanding, vulnerability assessments using models, and updated observations in response to specific storm events. In particular, observations were made to determine morphological changes associated with Hurricane Isaac, which made landfall in the United States first at Southwest Pass, at the mouth of the Mississippi River, at 0000 August 29, 2012 UTC (Coordinated Universal Time) and again, 8 hours later, west of Port Fourchon, Louisiana (Berg, 2013). Methods of observation included oblique aerial photography, airborne light detection and ranging (lidar) topographic surveys, and ground-based topographic surveys. This report documents data-collection efforts and presents qualitative and quantitative descriptions of hurricane-induced changes to the shoreline, beaches, dunes, and infrastructure in the region that was heavily impacted by Hurricane Isaac. The report is divided into the following sections: Section 1: Introduction Section 2: Storm Overview, presents a synopsis of the storm, including meteorological evolution, wind speed impact area, wind-wave generation, and storm-surge extent and magnitudes. Section 3: Coastal-Change Observations, describes data-collection missions, including acquisition of oblique aerial photography and airborne lidar topographic surveys, in response to Hurricane Isaac. Section 4: Coastal-Change Analysis, describes data-analysis methods and observations of coastal change.

Atlantic Ocean;Caribbean Sea;Gulf Of Mexico;Missis↗

USGS2019

Potential sea level rise for the Chitimacha Tribe of Louisiana

Situated in the Mississippi Alluvial Plain of the Gulf Coast Prairie Landscape Conservation Cooperative (GCP LCC), the Chitimacha Tribe is one of four federally recognized tribes in Louisiana. The Tribal seat, trust lands/ reservation, and adjacent Tribal owned lands are located near Charenton, Louisiana, totaling nearly 1,000 acres. The Chitimacha, with a population of approximately 1,400 people, are currently impacted by storm surge, which is expected to increase with climate change. The additional stress from storms will likewise increase the vulnerability to catastrophic impact in the event of a breach in the Atchafalaya Basin Spillway levee. A collaborative effort between the U.S. Geological Survey (USGS) and the Chitimacha Tribe has been initiated to provide resources and expertise to increase the Tribe’s ability to prevent, plan, and prepare for these environmental challenges. By enhancing technical skills, providing access to environmental data, and increasing awareness of environmental issues, the Chitimacha will be better prepared to plan and adapt to the environmental impacts facing their lands related to land use and climate change. For this project, USGS researchers asked how Chitimacha Tribal Lands might be impacted by future sea level rise scenario projections. These models illustrate some flooding within the northernmost boundary of Chitimacha Tribal Lands.

Louisiana↗